With spring coming up, many of us are already starting to get our yards and gardens ready for the growing season. Among the activities we may take on, there can be the managing of branches, sticks, and wood that may have been trimmed from trees and shrubs in the fall, over the winter, or just recently. In today’s post, I want to talk about how to integrate these resources into our green spaces, to support wildlife and the natural services they provide.
Increasing the diversity of our green spaces
In several of the posts that we publish on this blog, we recommend different actions that can be taken to increase biodiversity in our green spaces (see local ecotype plants, helping pollinators in small green spaces, and conserving parasitoids for some ideas). We know that increasing biodiversity improves the ability to control and restrain pests, increases wild and crop plant pollination, and in many cases leads to better soil quality. Among these practices, there is one that increases the physical complexity of our green spaces, providing nesting, shelter, and food resources to beneficial organisms. The practice I’m talking about consists of building wood and stick piles that can be established in our green spaces. The idea behind this practice is to create a space where birds, small mammals, insects, and even pest predators can find their preferred resources, and thus be attracted and present in our environments (learn more about the landscaping rationale for using dead wood).
What organisms are attracted by these piles?
Depending on the size of the pile and its composition (e.g., large logs, smaller sticks, a mix of them), different organisms will be attracted and may establish themselves in our green spaces. The presence of a mix of logs and sticks usually attracts birds, which may nest within the pile or may just spend time within the pile searching for food or finding shelter at different points during the day. These birds will certainly contribute to increasing the diversity of animals present in our green spaces and can also in some cases participate in the control of insect pests that we may not want in our gardens and yards.
Other animals we can observe in these piles are a variety of insects then may be associated with the decomposition of wood or that may use wood as a nesting or overwintering resource (e.g., bees, solitary wasps). While the former can help recycle the wood material and reintegrate it into the habitat, the latter may participate in the pollination of plants and crops that we may grow in that area or predate on unwanted pests.
Similarly, ground-dwelling invertebrates like millipedes and ground beetles can also find shelter under these piles, while the brush can also contribute to the nesting of pollinators such as (ground-nesting) bees, the overwintering of some butterflies and moths, and help improve the quality of the soil in that part of our yard.
Larger organisms may also be attracted to these piles, such as small mammals, amphibians, and even reptiles. Although we may tend to dislike these groups of animals, many of them feed on unwanted soil organisms and may help with soil quality, while others can actually control vermin through their predatory abilities. This is particularly the case of snakes that may find shelter in these spaces, which, while harmless to humans (the vast majority of snakes in Maryland are non-venomous, readily feed on rats and mice that may be present around the house.
How to build these piles?
These piles can take many different shapes and sizes, which depend in part on the materials and space available. When very large spaces are available (e.g., in the woods), it is recommended for these piles to be relatively large – at least 10 to 20 feet in length, and up to 8 feet in height (read more about these larger brush piles). In smaller spaces such as in urban or suburban gardens, these piles can be much smaller, occupying areas that may not be regularly used for other purposes. In all cases, it is ideal to build these piles using a combination of different types of materials, such as twigs and branches of different thicknesses, some logs, and even some branches that may still have dead leaves attached to them…always using healthy materials.
An important consideration when putting together these piles is that they should not be built leaning on or very close to wood-based structures or the foundations of our buildings. This is because of the potential risk of termite infestations of buildings if the piles are not physically separated from them. However, it is important to stress that establishing these piles has not been shown to be associated with higher termite infestations if the pile is not in contact or very close to the built structure. (You can read a very good discussion about mulch and termites from Iowa State Extension).
So, as you work on your spring garden, I encourage you to think about plant stems, logs, and branches not as waste that needs to be cleaned up, but as beneficial resources that you can incorporate into your available space.
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.
Anahí also writes an Extension Blog in Spanish! Check it out here, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!