DO THE WORK
Retaining & Creating Habitat Features
Habitat features are structures or arrangements of natural materials that provide hiding, feeding, sleeping, or other benefits to wild animals. They may occur naturally, or intentionally. Vegetation management projects can have the dual benefit of reducing wildfire risk and improving wildlife habitat diversity and complexity. It’s important to retain unique features and a complex understory that offers a mosaic of opportunities for forage and cover for wildlife.
Results and Benefits
This practice enhances wildlife habitat without increasing wildfire risk and fosters biodiversity, creating a healthier ecosystem, if done properly. Each habitat feature provides particular benefits, described below.
Conditions that call for this practice
Habitat features can be retained and created in all environments, as part of vegetation management activities. It’s especially important to use this practice where severe disturbances have occurred or where management activities have created a uniform forest with few habitat features.
Without proper execution, some habitat features can increase the risk of wildfire and its spread. Patches of shrubs and habitat brush piles, should be fewer or possibly absent where fire risk is very high (very steep slopes, or bordering very dense unmanaged vegetation) or you are highly risk averse.
This infographic from Wildlife-Friendly Fuels Reduction in Dry Forests of the Pacific Northwest is from outside our region but is an excellent illustration of different habitat features. Note: openings in the bottom illustration are exaggerated to make habitat features more visible.
Requirements
Knowledge
If your site has streams (even small seasonal creeks or drainages) or wetlands, it’s likely these are the most productive habitat features on your site and should be retained, enhanced, and potentially given more room to function fully.
Understanding how to retain or create habitat features without increasing wildfire risk is critical. For instance, building wildlife habitat brush piles away from low branches avoids creating a fuel ladder. See below for helpful hints. If you’re unsure, training, guidance, or advice from a professional is recommended. Compliance with regulations (e.g. CEQA and other environmental laws) is often satisfied by simply avoiding impacts to habitat features such as legacy trees, snags, streams, or wetlands. Avoiding impacts will “stream”-line permit approval and the compliance process.
In Practice
Snags
Snags are standing dead trees (or partially dead standing trees). These provide material for insects and fungi to colonize, which in turn creates food for birds (such as woodpeckers, nuthatches, and titmice) and other species. Cavities formed through foraging and mating activities also offer habitat to species like squirrels, blue birds, and if the snag is large enough, owls or pileated woodpeckers.
Leaving ~6 foraging snags/acre (up to 10” dbh) and 1 – 2 cavity nesting snags/acre (12”< dbh) is ideal, although numbers will have vary depending on goals and constraints. Leaving a single snag can provide increased habitat.
In order to keep snags from becoming fire hazards, keep them at least 10’ from other trees, outside of defensible space (0-100’ from the home), and away from areas of high human activity.
*If a snag does fall, it is important to get it to the ground so it does not lean on, or get caught up in, living trees, because that could create a fuel ladder that could cause another tree’s crown to ignite.” Arborists and foresters are best consulted when dealing with these hazardous situations.
Often snags are naturally created. They can also be created by professionals when a forest is too uniform. For example, you can take advantage of harvesting equipment to make some snags. Mechanical harvesters can top trees, leaving 8-20 foot tall stumps. Climbers can top some trees (creating jagged tops) or girdle 2/3 of the way up to make snags.”
Logs
“Logs provide ground level habitat complexity and cool, moist hiding cover for small mammals, amphibians and reptiles. They slowly release nutrients and water back into the soil and provide food in the form of insect larvae for woodpeckers and bears. They can also [retain soil] on steep slopes, helping slow water runoff and reduce erosion. Maintain well dispersed down logs on the landscape. Remember, the bigger the snag or downed log, the better!” Need a very rough range per acre. Logs should be at least 12” in diameter and at least 4’ from the trunk of any other trees so they don’t risk damage to the root systems. Don’t point the ends of the log at live vegetation, because if the log catches fire, its ends can radiate damaging heat.
Legacy Trees
From large mammals to the smallest invertebrates, large-diameter native trees often act as an ecosystem on their own. Large-diameter trees offer a range of important benefits to the ecosystem while providing significant carbon sequestration and storage. The large surface area of rough bark provides ample forage for bird species such as nuthatches and woodpeckers. Legacy trees provide perches for birds of prey like hawks and owls, especially if they have broken, twisted, or gnarled tops. They provide more shade and offer water retention through the duff they deposit over decades and centuries. Large diameter trees are more difficult to ignite and more tolerant of fire around them than smaller trees. Retain as many old-growth or large trees as possible, without crowding. “Thinning around these trees (1.5 – 2 times past the dripline of the tree) will help them be fire resilient and vigorous.” If such trees are near roads, trails, homes, etc, they may need an arborist’s or forester’s attention to evaluate hazards.
Openings
Openings are spaces where many of the overstory trees are missing, letting in light and air. This space allows young trees, grasses, and shrubs to grow and offer a wider diversity of cover and forage for wildlife. New generations of sun-loving tree species can grow in these spaces (e.g. valley oaks and western white oaks). Natural openings are more often curving, irregular, linear strips than circular.
Openings can be created or enlarged by removing less desirable trees and shrubs, or by limbing trees adjacent to a natural opening. Openings can vary from a few thousand square feet up to multiple acres, comprising 5-15% of your land. They are most appropriate for sites larger than 5-10 acres.
Patches
Patches are dense clumps of shrubs, or native trees that grow in clusters when small, that provide an important habitat niche for many species. They provide feeding and nesting habitat for songbirds, and browse and cover for mammals. If your project site is very high fire risk, or you are very risk averse, then patches of dense vegetation may not be a good component for you. Patches are simple to retain during thinning, if you plan in advance (see Thinning). A common patch size for larger sites is 30-50 feet wide and longer, potentially much longer, in length, with roughly 300-500 feet between patches. Consider where you can provide patches, potentially smaller ones, even along roads or ridges where more intensive thinning is the norm, to give cover for animals trying to move across these potential barriers.
Habitat brush piles
Habitat piles provide value to many species including small birds, quail, mammals, lizards, snakes and insects. And they can be used as an option for managing woody material.
Build piles away from overhanging limbs (or dripline) of trees, so that in case of wildfire the pile doesn’t scorch the canopy or root system. Habitat piles should consist of at least 5 layers of larger material to create structure. The top layer should be >12” of duff, leaves, and twigs. Piles’ footprints can range from 6×6’ to 6’x12’ and should be no more than 6’ in height. A good density is 1-3 per acre.
Shrubs
Many native shrub species (including poison oak) provide excellent fruit, insects, and forage for wildlife. Retaining or planting native shrubs will greatly enhance habitat, providing food and shelter for a variety of species. Shrubs can be retain within a forest or woodland, as long as they are located away from tree trunks and low canopies. Keep any dense area of vegetation separated from structures, roads, or high-traffic areas.
Timing Considerations
Work that disturbs vegetations is best done after bird nesting season, generally from March through August in Sonoma County. This timeframe covers nesting season for the majority of songbirds and raptors (birds of prey). If vegetation management must be done during nesting season, consider suggestions in the Nesting Bird Surveys chapter.
Equipment
Personal Protective Equipment (PPE)
- Long pants
- Long sleeve shirt
- Chaps
- Boots
- Helmet
- Leather gloves
- Eye and ear protection
Tools
- Hand saw
- Pruner and/or loppers
- Pole saw or a ladder to use with hand tools on smaller pieces
- Chainsaw
- Mechanized pole saw
- Peaveys, rock bars, or other tools for moving large diameter or heavy wood
Maintenance
Non-living features (snags, piles) decay with time. As piles collapse, or snags fall down, it may be time to create new piles or find other snags you wish to retain.
Related Practices
Managing Roads & Trails (coming soon)
Please note: this is a general guide. The specifics of how and when to do this practice will depend on many factors, including the site’s particular vegetation, climate and topography, history, and land management goals. Always consult with a professional if you’re unsure.
Do you have your principles in mind? Remember to regularly check in with your land management goals, to assure your practices and actions will actually achieve your goals.
Additional Resources
This brochure is from outside our region and uses plant species not found here, but it is excellent: Wildlife-Friendly Fuels Reduction in Dry Forests of the Pacific Northwest. Much of this Practice was adapted from this brochure or quoted directly.
Timing Considerations
Thinning is best done after bird nesting season, generally from March through August in Sonoma County. This timeframe covers nesting season for the majority of songbirds and raptors (birds of prey). If vegetation management must be done during nesting season, consider suggestions in the Nesting Bird Surveys chapter.
Equipment
Personal Protective Equipment (PPE)
- Long pants
- Long sleeve shirt
- Chaps
- Boots
- Helmet
- Leather gloves
- Eye and ear protection
Tools
- Hand saw
- Pruner and/or loppers
- Pole saw or a ladder to use with hand tools on smaller pieces
- Chainsaw
- Mechanized pole saw
- Peaveys , rock bars, or other tools for moving large diameter or heavy wood
Timing Considerations
Thinning is best done after bird nesting season, generally from March through August in Sonoma County. This timeframe covers nesting season for the majority of songbirds and raptors (birds of prey). If vegetation management must be done during nesting season, consider suggestions in the Nesting Bird Surveys chapter.
Equipment
Personal Protective Equipment (PPE)
- Long pants
- Long sleeve shirt
- Chaps
- Boots
- Helmet
- Leather gloves
- Eye and ear protection
Tools
- Hand saw
- Pruner and/or loppers
- Pole saw or a ladder to use with hand tools on smaller pieces
- Chainsaw
- Mechanized pole saw
- Peaveys , rock bars, or other tools for moving large diameter or heavy wood