Trees are most often planted for shade. The most important shade tree on the grounds of the house is usually located near the southwest corner of the house. If placed correctly, it will shade the house during the late afternoon in summer. Trees provide better shade than artificial structures.
The air passing through the branches is cooled by the perspiration of the leaves. Deciduous trees (trees that lose all their leaves every fall) save energy in summer by shading homes, paved areas and air conditioners. Small deciduous trees and shrubs, and especially those with low, dense branches, can also serve as effective wind barriers. You may know these soil particles: clay, silt and sand, and how they combine to form soils of different textures.
There is almost nothing you can do to change this type of basic soil; once loamy clay loam, always silty clay loam. The structure, however, is how these soil combinations combine with air pockets to form the soil that we excavate with our shovel. It's essentially how tight those tiny soil structures are together, and many of our urban soils are simply too tight and compacted. The act of digging, in the right moisture conditions, will help to rearrange such a structure, decompose compacted soil and increase the water and oxygen holding capacity of the soil.
Sometimes there is no substitute for physically breaking the ground to release its potential. Between trees, their landscapes and their similar flora and fauna, there are surprisingly complex relationships that we are just beginning to understand. The issue becomes even more complex when humans are included in the equation: about 2 billion people rely on forests alone for work, food, shelter and water. Of course, trees play an important role in sequestering carbon from our atmosphere.
With our colleagues from Royal Botanic Gardens, Kew, Botanic Gardens Conservation International (BGCI) and partners around the world, we helped develop a list of “10 golden rules” to improve tree planting efforts in terms of carbon sequestration, biodiversity and human livelihoods. For example, the BGCI project to conserve Malawi's national tree, Mulanje cedar, not only resulted in the planting of more than 500,000 trees, but also created more than 1,000 jobs for the local community and trained more than 200 people in nursery management and business development to manage 10 nurseries community of plants. Restoration works best when it has collateral benefits for local livelihoods. Later this year, we will publish Global Tree Assessment (GTA), the first conservation assessment of all known tree species in the world.
This report will provide a conservation roadmap that will put our 10 golden rules to good use. Errors in tree placement or construction make a huge difference in the size of tree conservation areas and the amount of root and crown pruning required. Cutting or lowering the ground level near a tree severely damages tree roots, leading to decreased health and even death. Sanctions must be large enough to emphasize that large trees can be worth thousands of dollars and even small trees can cost hundreds of dollars to replace them.
A simple tree conservation plan shows the location of the house, the driveway and the trees to be removed, invaded and retained. Attempts should be made at leveling and site plans to eliminate or minimize construction impacts on decent trees by removing less valuable trees and moving or altering grading, buildings, utilities and other infrastructure elements. For example, a medium-quality tree could be marked for removal to prevent invasion and pruning of a higher-quality tree. DAP tree shovels or other equipment for moving trees up to 10 inches are available in many communities.
In an inventory, a form is used to collect information on tree species, trunk diameter, height, crown size, condition, suitability for conservation and maintenance needs. Shoes designed for pillars or slope beams, which reduce pruning damage to tree roots, can be used when working near tree trunks. Accurate tree size and location information allows developers, engineers, and landscape architects to compare the location of trees with the location of buildings, cuts, infills, retaining walls, streets, utilities, heavy equipment routes, and other proposed construction activities. The right tree in the right place also means tree selection and location to minimize conflicts with power lines and other obstructions.
All the work invested in the tree report and the tree conservation plan can be lost by carelessness. Trees that are not surrounded by infill have a noticeable flare in the trunk at the ground line, while trees buried in the infill do not have a trunk flaring. Problems caused during the construction phase due to inaccurate information about the location and condition of trees can be costly in terms of health, time and work interference of trees. Matching the attributes of a species to the constraints of your site will ultimately determine how well your new tree delivers the benefits you wanted from your tree in the beginning, its “why” to plant in the first place.