This is installment #4 for ecological, site-specific considerations for siting Green Built structure on undeveloped, forested land. This posting will focus primarily on the living resources of the land: natural communities, native plants, and wildlife. Post #5 will focus on the non-living resources of the land, all of which are important in planning stages.
Based on planning phase mapping & research (see Blog #3), potential “hotspots” where critical resource concentrations might be found are often surveyed first with emphasis on mapping the highest quality, most intact habitats and resources on the property. Note that initial property-wide surveys are most effectively followed by detailed road and home-site specific surveys within potential disturbance areas to help prevent site-specific problems.
Natural communities are relatively stable, naturally occurring and somewhat predictable alliances of dominant canopy and understory plants that occur throughout the landscape. They are critical as the basis for which rare and even common plants and wildlife can thrive. Even on a 5-10 acre tract, they can be as distinct as rooms of a house. Mapping these areas allows us to compare forest age, size, quality, composition, vegetation variation, as well as the sensitivity of various areas. Most critical to find and map however are “rare” natural communities, a concept that is too lengthy to explain here, but which involves less common assemblages of physical and vegetation conditions such as cliffs, seeps, and various “subtypes” of more common natural communities. Rare or common, those having the least impacts, greatest stand age, quality, and native conditions garner greater consideration for least impact site design.
Botanical surveys typically focus on locating rare species (as listed by the state) and areas of high diversity or integrity (even w/ low diversity) that should be avoided, and even restored and enhanced. Prime examples of areas to avoid are those with obvious lush carpets of wildflower and ferns where soil disturbance can be catastrophic to vegetation and wildlife. Often, when impacts cannot be avoided, these plants can also be relocated (esp. via root division) and propagated.
Wildlife is more difficult to survey than plants: they move, they come & go, populations can fluctuate wildly and even when they are there – they might never been seen. Key habitats such as rock outcrops, talus, standing & fallen dead trees, and unusual ground-level topography provide clues. Groups such as Neotropical migratory songbirds, salamanders, reptiles, butterflies, and some mammals can be surveyed with relative ease…however, wildlife surveys are rarely comprehensive due to the length of time. The key is to avoid not only denning sites in soil and trees – but to entirely avoid impacts during the peak breeding season for birds May through June.
These resources, along with water, are mapped and inventoried in detail, especially within road & homesite corridors and following some additional fine-tuning based on physical features of the land, a plan can be devised and mapped that will attempt to minimize soil and forest disturbance, but actually “recycle” and incorporate some of the natural elements that cannot be protected.
By Kevin Caldwell, guest blogger