Backyard Biodiversity & Ecosystem Health; Protected by Beetle Banks

Are you looking to begin another project in the garden for the sake of wildlife? Or instead are you perhaps looking to defend your garden from the pests that munch on your flowers and crops?

Prepare to celebrate then, for you’re about to hit two birds with one stone!

As is implied by the featuring title above, this is a method that aims to host insects whilst being able to protect a certain something, and in this case it’s the greenery in your garden. Whilst on the topic I want to shoot down any uncertainties, the “beetles” in this title is purely for the sake of alliteration, and is really in reference to the general insect population.

With that out the way, I hear your next question coming;

How will introducing more insects into my garden stop insect pests? Surely it will increase my troubles..!

That’s an easy answer as just as there is a food chain amongst animals, there’s a food chain to insects within their own order, in which there are insects that predate other insects and are known as insectivores.

Going from here is intuitive! As we own habitats that’s inviting to your pest species (your crops & other greenery being their food source & shelter), we can introduce a habitat that is capable of hosting insectivores. There’s a bit of art & science to it, so I will explain in more detail in the next section.

But for now know that this is the origin of Beetle Banks, a practice often implemented by farmers seeking to encourage these predatory insect species and in doing so, reducing the time, effort & cost needed to employ other pest control methods such as pesticides.

And there’s the concept!

Now let’s move on to the practical element.

The Operation of a Beetle Bank

We’re starting with a bank, a long strip of (preferably) raised soil that resembles a speed bump, though the bank can be a fair bit taller. It’s the “raised” height feature that gives rise to a slight difference in the ground condition that effects the grasses that grow from it, creating a mosaic of freely draining soil, differing levels of sunlight exposure, wind buffering and so on, that encourages different grasses and other perennial plants to compete amongst each other to maintain a balance of various species.

Off of this bank we’ll be growing thick tussocks of grass and/or plants that can act as an insects ideal habitat, whilst allowing for safe residence and movement similar to a wildlife-corridor. These insects will do a lot for you, including acts that go unnoticed such as balancing soil nutrition, organic decomposition, or ground aeration, however the overarching goal that you can easily notice is controlling pest insect populations near you.

As a extra add-on, this bank that fosters an array of insects also provides a beneficial food resource to the fauna that prey on these insects, most importantly through the winter when food resource are thin. For any wildlife enthusiasts, you may be excited to hear that other wildlife such as hares, partridges, and harvest mice may also inhabit the banks on occasion.

There is a benefit to a balanced ecological system that will benefit your green space, which you read about here.

Fixing an Wildlife Issue, to Fix Yours!

We’re lacking in a number of habitats for certain wildlife currently, and whilst there are still dense grass zones and intact hedgerows, it is an issue of unconnected habitat corridors and the low quality & quantity of habitat area compared to the past. By providing a space for these insect species you can encourage a local population that in the Spring will move to hunt amongst your crops & flowers, and furthermore even allowing them to overwinter in dense numbers.

Modern dense grasslands typically lack the correct grass species mix, often dominated by other species, and don’t create that ideal habitat to host beneficial insects. Then there’s also the issue of overly-expansive fields in which these small of stature insects may takes weeks to cross if they aren’t able to fly. By correctly positioning a Beetle Bank, you can allow insects safe yet quick access to nearby resources.

The concept of mid-field refuges may also be of benefit to you, as they are akin to hedge-banks with no woody shrubs, available as refuge stepping stones during long distance travel in which predators can overwinter and spread to their hunting grounds in the Spring.

In these conditioned environments the insect population that inhabits these banks can be even higher than the traditional existing field boundaries. Which is exactly what you want.

Because of the low number of suitable habitats for these predatory insects, the beetle banks you create will become hugely dense with these sleepy mini-beasts during the winter, only to spread out during the Spring. This of course means that your garden receives the the healthiest does in the reduction of crop pest species by virtue of it’s proximity.

As a final additional benefit, this is a project with easy maintenance, requiring mowing only during the first year, and after which it is best left unmanaged! So after the hard work of creating it, all that’s left is letting it carry on doing as it likes.

Speaking of which, let’s get into it!

Building a Bank

1. You’re aiming to create a raised bank of soil, whether it follows a straight line, fit’s into a corner, or shaped as a circular mound. You can raise for up to 40cm in height, with a width of your preference.
3. September is the best time to hand sow your soil with a mixture of perennial grasses, but aim for a high percentage of “tussock-forming” and/or “mattock-forming” species (listed below), alongside a mix of fescues, bents, or even tall-growing wildflowers. If you can’t do September, then the following Spring is a good option.
4. Up to three cuts in the first Summer can be helpful after the sward reaches a height of 10cm, one cut for every time it reaches this height. By doing so it controls the encroachment of annual weeds, and encourages new shoots of grass to grow to make dense, tussocky grass.
5. At this point your beetle bank will have established itself and be largely self-maintaining! You will only need to cut the grassy strips to regenerate dead tussocks, which will likely be several years in-between.
6. Two-to-three years after the initial sowing, these banks will have developed into a suitable habitat for your overwintering insects, benefitting your garden with a healthy food chain.

Ever-important Plants

Native plants that, once established, will create strong connections to the wildlife that is naturally present within it’s surroundings. These aren’t the only species of plants you have to use, and can eb taken as reference.

Grass mix containing tussock and mat-forming species;

1. Cocksfoot
2. Timothy
3. Red Fescue
4. Ribwort Plantain
5. Crested Dogstail
6. Tufted Hairgrass
7. Tall Fescue
8. Sheeps Fescue
9. Fescues & Bents

Tall or mat-forming wildflowers;

1. Sunflowers
2. Coriander
3. Borage
4. Buckwheats
5. Yarrow
6. Tansy
7. Oxeye Daisy
8. Teasel
9. Black Knapweed
10. Red Campion
11. Musk Mallow
12. Wild Carrot

The added benefit of providing additional mixtures of wildflowers & grasses is providing food and further habitat for multiple species, including endangered or struggling species. With local native plants, the restoration of the surrounding ecology can be supported.

And there you have it!

Whilst they make take a while to get rolling, they are an interesting feature akin to shaggy green hills to have displayed in the garden, teeming with tiny critters who’s sole goal it’s to help you keep pests populations down.

I’m sure you can get creative with the design to create your own unique backdrop suitable for your personal garden designs. I’d be very interested to see the many outcomes from this.

If you’re craving more of a similar brand, feel free to read more on the Habitat Management section in my blog!

Happy Reading!

A Wildflower in the Garden

A flowers born to the wild, a Wildflower. It is dissociated from the common term “flower” due to one differing characteristic, and that is that they grow without deliberate human help (i.e. sowing or cultivating). In this sense, any flower may be a Wildflower if it’s seeds has found their way into a suitable habitat and spontaneously grow when the conditions are met.

There are many ways to separate flowers into distinct categories, but Wildflowers is a widely recognised term in Habitat Conservation due to their self-propagating ability.

All flowers are of a species that is specially adapted to lead wildlife to do the hard work for them, in regards pollination & seed dispersal. In the end if the conditions are right, flowers tend to gather in particular areas as to form dense networks named Wildflower Meadows.

These Meadows have distinct, critical features that make their habitat successful, and in conservation “successful” means that the presence of these wildflower species offers opportunities for wildlife to support itself throughout their lives.

And when it comes to how we benefit, the presence of a wildflower patch means low-maintenance land that will self-seed their various flowers, attracting a dense reserve of wildlife and protecting soils.

Specifically, what is a Wildflower Meadow?

A wildflower meadow is a variation from the standard grass meadow, in that it is dominated by seasonal wildflowers alongside the secondary presence of short, permanent grasses throughout the year. Unlike ‘cornfield’ varieties of flowering annuals (think fields of poppies) that prefers fertile soils, wildflower meadows grow on low-nutrient soils where the vigorous grasses cannot dominate nor outcompete them.

Benefit to Wildlife

Wildflower meadows are naturally competitive. In the natural world, flowers dominate the nutrient poor soils, focussing instead on storing energy for a short burst of flowering at the right time of year, rather than competing long-term with leafy & growth-focussed grasses, or shade-heavy shrubs & trees.

But funnily enough it is this characteristic that provides a very interesting resource for wildlife. The Wildflower’s focussed approach of rapidly producing attractive flowers for pollination allows multiple species of flower to survive in close quarters by reducing the competition for nutritional resources, and instead on luring in pollinators for sexual reproduction. Essentially, the most attractive wins rather than the best resource-gatherer. This approach results in creating a dense network of tall, complicated, and resource-rich stem, leaf & root structures, surprisingly lasting for a fair length of the year as old plants die and new ones replace them. The self-supporting & sprawling plant networks allows normally grounded creatures an extra elevation upon which to live in, alongside the presence of both resources and safe heaven on literally all sides. The dense foliage protects from predators above and below, whist an abundant reserve of nectar, pollen, sap, insects, mammals, reptiles, etc is provided within the tangled web of greenery. And whilst these resources are only present during the most sun-energy rich periods of the year (Spring & Summer), this presence of flowers alone is worth the risk for most species. And in this vein of thinking that the foliage grown by flowers creates a useful dynamic through heat & water retention due to it’s many insulative layers against sunshine and wind, their high water transpiration rate, and finally their “short height”. All this allows them to retain more heat beneath their upper canopy, whilst further down maintain a cooler yet still muggy and damp temperature; a preferable variety of options for many species.

It is through this dense thicket that Wildflower Meadows multiplies & compresses the food chain into a relatively compact area. Even in the skies above, far away from the flowers, linger a multitude of birds eyeing up the fringes & glades in flowering fields in the likely chance of prey. Or perhaps similarly to other creatures, they are simply looking for nesting material.

Regardless, the benefit to wildlife is self explanatory at this point, and that’s without going into the well portrayed discussion about pollinators.

Benefits to You

Due to the complex & compact nature of wildflower meadows, the soils beneath them are tightly bound together by fine, overlapping root systems to create a very stable soil. Thus when it rains, there is little in the way of run-off from water, and no loss of nutrients. If you have land on a slope, dedicating a portion of that area to a band of wildflowers is a good buffer for poor weather conditions, thereby ensuring your garden is neither flooded nor stripped/saturated with nutrients to encourage weeds or vigorous grass growth.

And on the topic of soil nutrients a typical garden lawn’s grasses have shallow roots, making use of only the surface nutrition, whereas a variety of (flower) species tend to differ their root structures and dredge up the nutrients stuck further down & throughout the the soil. As you’ll learn later on, you cut & remove the Wildflower cuttings from your meadow, allowing you to take those nutrients to be redistributed to wherever you see fit.

As a time saver, wildflowers require you to reduce the amount of mowing, going so far as even just once or twice per season. And with the removal of herbicides & pesticides (neither need controlling in this meadow), you reduce your price costs and run-off water pollution into the surrounding soil.

And as wildflowers tend to do best in poor nutrition soils, you’ll also quickly be able to see where these low-nutrition areas in your garden are if you notice your wildflowers re-seeding & growing elsewhere. You’ll be able to counteract this with your cuttings, or extend/relocate your wildflower patch.

Focussing now not on soil but air, it is due to their vigorous & quick growth rate that Wildflowers also do a wonderful job at removing a range of pollutants from the air, filtering & improving the air quality. They use the pollutants as a food source before they eventually die and lock it into the soil for future generations of growth. On the other side of that coin though is pollen… hayfever sufferers will notice this airborne pain.

Interestingly though, flowers have formed other deep rooted into us aside from sneezing. Our emotional responses trigger in response to seeing blooming flowers, with the sight of them alone causing lowered blood pressure and stress hormone production. For good or bad it seems as if our connection with flowers goes beyond mere appreciation.

To summarise, the introduction of a Wildflower meadow brings a more holistic result. Due to the unique nature of these meadows (water filtration, soil erosion control, extensive nutrient recycling etc) and your maintenance, you’ll see the presence of wildlife in a fairly new format. A ‘balancing’ effect on your garden will arise in the presence of a variety of healthy wildlife populations. Species have evolved in the expectation that other wildlife will be exerting various behaviours upon them, so you’ll see your garden reacting to these introduced behaviours.

As a final and fairly obvious observation, wildflowers also look & smell nice.
So there’s that aspect to enjoy!

Managing Land into a Wildflower Meadow

Jumping straight in, we’ll go over how to set up, maintain, and generally manage your wildflower meadow to the end goal that suits you & your garden.

Introducing & Establishing a New Wildflower Meadow:

The best time to create and sow your meadow is in autumn.

1. Choose the right time: The overall best time to create & sow your new meadow is in Autumn, however the preparation can be done at any time of year. Sowing in Autumn simulates natural seed dispersal times, allowing them to develop through the Winter.
2. Choose the right spot: you’re looking for a spot that’s sunny throughout the day & relatively open. Don’t worry if that spot is sloped or flat, you can position it however you prefer.
3. Soil nutrition: your soil might be too dense with nutrients (i.e. fertile) to host your wildflowers, so other than checking your soil first, you can jump straight in and remove the top 3 inches of topsoil from your chosen patch. This will likely be the hardest part of your wildflower journey as it involves muscles & spades, or a turf-cutter for an alternative option. As a more time-consuming yet less intense effort, sow plants that require many nutrients, let them grow, and then cut them down & remove the cuttings. This will lower nutrient levels over time.
4. Soil & Weed Work: rake up your soil so it is nice & soft, and remove any roots or remaining weeds. Once you’re looking at your fine, bare soil you’ll be ready to start sowing seeds.
5. The ‘Wild’ in Wildflower: sowing a mixture of flower seeds does take some of the wilderness out of the approach, however in the following years these species will continue to seed & sow themselves, and as you get visiting wildlife to your garden, you’ll start seeing new wildflowers popping up as they get dropped in your soil.

In the first year of growth it is important to encourage the growth of wild flowers over the competing grasses, weeds, or woody shrubs. After the sown or naturally occurring flowering plants initial growth the following Spring/Summer, return every 6-8weeks to mow/cut down to a height of 5cm above the ground, and repeat this every 6-8 weeks during the Summer season during this first year of establishing your wildflower meadow.

After entering the second year, the method of management lies in not cutting after April until July/August. The aim is to never continuously cut back your plants as they may never grow to the seeding stage, yet avoiding to (repeatedly) cut-back late as this would result in your flower meadow becoming overcome by tough, competitive grasses with lower flower diversity.

To encourage a Spring Flowering for your wildflower meadow, aim to mow from late-June to October, and on the other hand if you prefer Summer Flowers, cut between late-July and March. For those of your who’s meadow may be large enough, try cutting different portions of your meadow at different times of the year from early-June through til early-September. This approach brings the greatest diversity in grass height and structures.

When you do mow your meadow(s), aim for a low sward height of roughly 5cm. Allow the cuttings to sit on the ground for up to 48 hours to allow seeds to fall through disturbances, and the local fauna to relocate to continue a balance population. If you are able, you can encourage this by allowing a section of your meadow to remain uncut for these species to inhabit during winter periods. Rotate uncut areas on a 3-4 year cycle to prevent it becoming dominated by vigorous grasses.

Ensure you remove cuttings after leaving them for a few days, as wildflowers thrive in low-nutrition soils where they cannot be outcompeted by nutrient-dependent grasses & woody shrubs. If left alone, the cuttings will return to the earth to be decomposed and release it’s nutrients back into the soil.

Long-term Maintenance

In surprising contrast to normal flower beds, the maintenance of wildflower meadows is incredibly small. There is no need for any additional watering (though consider in heatwaves) and no supplementary nutrients, doing either alters the natural balances that allows wildflowers to dominate since many of our native flowers survive by colonising our nutrient-lacking land. By mastering the schedule of mowing & nutrient removal, you have done enough to open the landscape to wildflowers.

Issues

Akin to wildflowers, certain weeds also thrive in wildflower habitat. Whilst they are simply weeds from our perspective and still are able to benefit wildlife, they may also dominate your meadow or offer an unappealing flower display, thus you may want to remove them before they set seed. Nettles can be stopped through simple repeated cuttings. Others, such as docks and thistles, can be pulled out by (gloved) hands to limit their returning capabilities.

Similarly grasses can start to become an issue if the cutting regime because interrupted or neglected, or you struggle with maintaining low soil nutrition despite your efforts. Here you can introduce certain seeds (for example, Yellow Rattle Rhinanthus minor) to control the spread of these grasses in an area due to their semi-parasitic nature towards grasses, or antagonistic natures.

General Advice

• Aim for the first cutting(s) to be around 5cm, but up to 7.5cm is also tolerable. Any subsequent cuttings can be at 4cm.
• In the first few years, you’ll likely notice a generous amount of nettles or docks. They will have lain dormant and begun generating once your soils were readied for wildflowers, as they respond well to disturbance. Either allow them to stay or remove them and over time they will disappear.

There are always many approaches you can consider undertaking when it comes to managing your garden for wildlife, yet wildflower meadows are one of those powerfully charismatic approaches in the conservation field that seems to go hand-in-hand with all gardens.

Armed only with the essential knowledge of when to mow your garden anyone can create a moving display of flowers, primed to benefit your wildlife.

I hope you enjoy any future meadows you create, or even just a new appreciation for the underpinnings of what is happening underneath your own garden lawn.

Cavity Trees: From Living Dens to Dead Snags

I like to think that it’s a long-established rule that we all try to avoid creating holes in any living being, to which I personally put people at the top of the list. And that’s generally a trustable rule-of-thumb when working with nature as well, since I have a reasonable confidence that most of everything in this world would appreciate that basic practice. And in relation to todays topic, it’s rather unsurprising that trees would rather not have holes in them either.

But unfortunately for trees they are just really, really accommodating locations to have holes in, no matter where the hole is on the body. So setting aside a trees personal feelings, these holes act as cavities (holes, hollows, cracks, fissures etc) to host animals, insects, lichens, fungi, and mosses, all of which are drawn to these cavities as vital safe shelter, an easy resource of foodstuff, and if well-established over the years, a promising resource of materials to express various behaviours.

So by encouraging or introducing a cavity tree into the local habitat, we can provide a increasingly rare habitat for wildlife that fulfils many functions.

Before we get to the how-to’s, you may have noticed I have yet to mention either Dens or Snags, and how they relate to Cavity Trees. Unsurprisingly, the terms Snag and Den both refer to trees with cavities, hence both are “Cavity Trees”, but any further than that and we begin to see that they are technically two different habitat types. Den trees are alive & persistent despite the damage a cavity would bring, having had holes formed within their trunks via decay, local wildlife, or mechanical wounding. Snags on the other hand are dying or dead trees created through the same process as Den Trees, yet pay the price and fail to ultimately survive the process through resulting illnesses, dire injury or instead, regular old age. Whilst the two seem similar, it’s the end result that means all the difference.

Both are alike in that they are important for many species of birds, mammals, reptiles, and the aforementioned fungi & mosses, creating a natural and long-lasting reserve throughout the year for nesting & protection from the weather. But it’s a Den’s ability to stay alive that allows wildlife to make long-term use of their features, as the Den will continue to live for perhaps hundreds of years to come and provide co-beneficial relationships to all parties involved. Alternatively Snags are important in that they fulfil all these characteristics whilst providing a stronger medium for fungi, mosses & lichen to grow, which in turn attracts & invertebrates within their aged & rotting cavities and dead wood limbs. This rather diverse offering shows itself as further foraging opportunities for birds & mammals.

The presence of Cavity Trees diversifies the pre-existing habitat by providing an area that is different from soil-bound habitats, yet doesn’t rely on the canopies & local geology to provide height. As with every new habitat, it is about the unique opportunities provided and the species that are able to make the most of them that create a functioning & interesting ecosystem.

And finally, in your benefit, is that you can introduce a cavity into a tree with only the initial investment of effort, as it is self-sustaining afterwards, to which afterwards offers a strong feature for your garden as the cavity is explored & overcome with wildlife.

Perhaps this rare habitat will give you a prime observation area to see unique & interesting species. So, shall we see what we have to do to get started?

Before you begin, the Considerations:

As you look about your local area, it’s the general thought that a total of six den trees and/or snag trees per acre (With trunks between 12-18 inches thick) is considered a good result for wildlife. If you think your area is lacking such cavity trees and you’d like to go the extra step, examine live trees with the right thickness (12-18 inches) for any defects that could lead to cavity formation.

If you’re looking at converting a tree into a cavity tree, thinking about the species of tree can be helpful in the long run. Species of White Pine, Red Spruce, Eastern Hemlock, Sugar Maple, Beech, Yellow Birch, Elm and Oaks will all stand for long periods of time, even as dead trees. Other tree’s will do well as well, but it may be worth doing a little research to see how they respond to damage, and signs of illness.

Encouraging Cavity Tree Formation, and also, why you?

The earliest tree-felling practices recorded indicate that our ancestors cut down only the healthiest, optimally developed trees for their material needs, and this approach was mostly due to the intensive time & energy it took to fell a tree back at that time. This practice left an abundance of cavity trees for Wildlife as a side-effect, as the ignored veteran trees are more inclined to cavity formation, as the slow natural process of cavity formation & microhabitat development takes time to establish itself.

In recent year we are able to see the worth in encouraging cavity formation, and so wildlife does not have to wait for natural causes to slowly occur.

With large, old trees being the staple for cavity formation, conservation efforts aim to accelerate ecological processes to mimic the features of a mature tree and it’s connection to respective woodland. The restoration and creation of both forests and wooded pastures poses a unique challenge, as it take a long time for trees to reach a acceptable age to develop, establish and accumulate the captive microclimates

This is why if you decided to create your own Snag or Den it would be an meaningful effort, since after all a large proportion of aged trees are present within gardens, having been left untouched for years.

Even more so as our tree harvesting evolved with time, our more recent ancestors began actively improving tree ‘quality’ to meet wood material demands, which resulted in repressing cavity formation.

In modern times, practised has evolved into a myriad of situational & factorial decision making balancing between ecological and economic pressures. And when it comes to rare species and habitat, the underlying preference is to conserve, restore and encourage. And in lieu of this, people are encouraged to retain their cavity trees rather than see them as a concern for trees health.

So I won’t keep you waiting any further, here, the 3 baselines that form a rough outline of the type of cavity tree that would provide the most benefit to wildlife, the tree you want to pick.

1. Use a large diameter (tree trunk ‘width’) cavity tree where available, this being greater that 25cm, though preferably greater than 40cm.
2. Potential for cavity formation in the uppermost trunk are more valuable than those in the lower trunk.
3. Present with at least ten other cavity trees upon one hectare of land to produce the most productive wildlife benefits.

Hopefully you’ll be able to recognise a tree in your garden that would fit these parameters. From here, let us look at how to create your own cavity tree.

Whilst cavities in nature are the result of decay following injury and/or disease, it’s now a feasible action to create man-made cavities. One benefit to this is the instant result, though it may be rough around the edges so to speak. But if you take a less direct approach the hollows that form in trunks & branches can be formed years after the event, forming a naturalised microhabitat. It is up to you to decide how you would like to make use of your chosen tree, as wildlife will still put it to use, but you may prefer a particular outcome. The methods listed below may result in cavities in the long run. Perhaps you have a tree that you are torn on keeping, so instead of removing it you may decide to experiment with it. Of course keep in mind damaging any tree may result in long-term damage, disease & death, but if you’re confident in your choice then it is a perfect time to try your hand;

• Remove a branch with a pruning cut made too close to the trunk.
• Remove a large, major branch to a similar specification.
• Breakage of a large, major branch. This damage can occur semi-naturally.
• Topping [removing portion from the upper trunk] the trunk and/or branches.
• Cutting a large, major root – typically results in ground level cavities.
• Cutting through a group of roots – similar to previous.
• Considerable damage to the trunk – this most likely occurs naturally, but you may be able to reproduce the effect.

Consider the outcome of each approach, taking the height, size, positioning, and ease of doing so as factors in deciding your next course of action.

A more direct approach would be drilling or cutting into the tree’s trunk to develop a cavity. This is a very intrusive process that can result in large damage to the tree if you go at it without a plan, but the results are instant. If you have the option, perhaps first attempt this with any dead-standing tree stumps, or a tree that has had it’s limbs removed and leaves only the trunk behind. If you decide you are confident, use caution and plan the design of the cavity beforehand.

Temptations

You may be inclined to add additional features or alterations to the cavity, but be aware there are some pitfalls to be wary of.

1. Old practices of “Tree Care” included filling cavities in an effort to strengthen the trunk. You may decide you no longer care for a cavity, and want to fill it in. Certain materials are inflexible and abrasive, and as the tree growths & sways in the wind, the abrasion enables decay to enter into the living wood.
2. Don’t be too tempted to add further details after the initial cut, such as adding a channel for water to drain out of. Further damage puts Trees at risk, especially if stagnant water is present at the site of damage.
3. Whilst it is good to have a cavity tree in your garden, don’t feel the urge to do so to all your trees. Tree’s avoid cavity formation where possible, so whilst it is good to offer rare habitat to your wildlife, trees support wildlife in a great majority of other ways as long as they are able & healthy. That being said, if you decide your garden is able to support more than one cavity tree, select differing tree species as they will offer unique niches.

Overall Benefits to Wildlife

We have a tendency to remove older trees due to their safety risks, but the consequence is a greater rarity of naturally appearing cavity trees, at most appearing in 10% of standing trees. Their loss is noticeable, as these are the natural nest boxes for many bird species, and provide microclimates for an abundance of species. These microclimates provide opportunities for biodiversity, a niche for specialised life of plants, fungi, and the various species that desire dark & humid conditions to flourish.

When cavities appear in older trees they often appear in numbers, especially as time goes on as the tree ages and accommodates species in abundance. Depending on the location of it, it may vary in size & design, possibly being a crevice, loose bark, decayed & broken limbs, burns from lighting strikes and so on. Even more so than all of these though are hollow trees, an especially valuable resource, and they often come endowed with ivy & honeysuckle, becoming heavily carpeted and insulated from outside factors, a true microhabitat.

No matter it Snag or Den, a tide of species make use of them. Owls, starlings, nuthatches, flycatchers, tree creepers, redstarts, jackdaws, and various small woodland birds all make use of these cavities, as do bats, mice, and a wide selection of insects. Internal nesting is individually designed to suit the species unique requirements, but it is the cavity that provides a safe refuge from weather and predators alike to do so. The abundant presence of wood-boring & loving insect, as well as tree saps, fungi, and mosses, provide a rich source of food in their own home.

Interestingly it is a useful feature of both Snags and Dens that once they fall naturally or are felled they are already primed to immediately provide benefits to wildlife as a new habitat niche, allowing wildlife to continue to express both new & different behaviours.

Snags especially, as they deteriorate, provide various substrates on which insects, plants, mosses, lichens, liverworts & fungi make refuge of, and in turn are prey to birds & bark-gleaning species. This platform upon which provides many foraging opportunities within it’s small but complex structure.

And naturally to take advantage of this promising offering, there are even species that create their own cavities, the well-known Woodpeckers are one of them, and they choose ideal tree species that decay quickly to do so, these being Ash, Birch, Alder, and Beech, as this suits their unique requirements.

In this theme, of the Birds and Mammals species that “use” cavities in trees, there are two distinct groups they are divided into. ‘Primary’ cavity users have the ability to create & excavate their own cavities, in contrast to ‘Secondary’ cavity users which rely on pre-existing cavities. The primary species list is far shorter than the extensive list of secondary users, but over time cavities are created and abandoned, creating space to host many species of ‘secondary’ cavity users. It is this that makes the presence of the ‘primary’ species all the more important as their presence will create further habitats for a wide variety of species in the absence of naturally occurring cavities. Otherwise, it is up to humans to create further cavities.

As you can see from this brief, deep delve into the background of a deceptively simple, easily overlooked fragment of a whole scale habitat, it is rather stunning what is happening within the confined spaces of Snags & Dens without us being able to see inside their often lofty heights.

So what I would take away from all this is that it’s also what’s on the inside that counts!

Benefits for You

This is one of those times where I’ll tell you, and possibly understandable in this case, that I can think of little direct benefit for yourselves from this conversation practice, aside from being able to appreciate nature to a greater extent in your garden. I could tell you that having a rich amount of species residing in your garden will bring a host of positives, but I personally count these results as passive. Passively, it’s presence would increase the natural productivity of your garden by including more species within the natural cycle, with the cavity’s microhabitat supporting a veritable host of species that in turn supports insects, then their predators, and so on. Respectively each animal would provide a service to their surroundings, which could be nutrient redistribution, population stabilisation, pollination, re-seeding, behavioural expression and you get the idea. Their presence is noteworthy for wildlife, and your garden, as a second-hand effect.

But you would have to be creative for you to create decisive & direct self-benefitting return from a cavity tree.

Of course as previously stated, the easiest method is if you are in the same mind of thought as me, appreciative of both the environmental and aesthetical results that it will result in. Simple things.

But as an Economic or other personal benefit, there is not much to be done, and instead, it will be up to you to determine a practical use or value. Look to see what occupies your Snags & Dens, as a method of benefitting may arise from species that often interact with this new microhabitat. A species that would eat pest species of certain crops & flowers perhaps, or provides a seasonal presence who’s behaviour indicates the occurrence of a certain event.

Often times there are many creative methods of benefitting from the world around us, from ancestral practices to the newly discovered, but it is out there somewhere yet forgotten or unknown.

Maybe you will find an answer?