What is close-to-nature forestry?
Some harvesting systems attempt to mimic natural forest processes of death and regeneration. Harvesting systems which emulate this process by selectively extracting individual or small groups of mature timber trees while allowing natural regeneration are often known as close-to-nature forestry. Under these conditions harvesting mirrors the way natural events, such as tree fall, results in the creation of small openings within the forest. These openings in turn give smaller trees, saplings, and seedlings the light and space to grow and replace the fallen tree. If the rate of regeneration matches the rate of harvesting then sustainability is achieved.
Such approaches are not new and have been used by certain communities for centuries. Increasingly they are becoming popular in Europe. A major difference, from an economic standpoint, between close-to-nature and standard forestry practice in New Zealand is that rather than the harvest occurring in rotations (like is typically done in pine plantations), a much smaller continuous harvest occurs thereby generating a steady, rather than pulsed, income stream.
Close-to-nature approaches involving native species have clear benefits for the environment. Most obviously, native forest animals have co-evolved with native tree species and therefore a forest based around native timber species should be more biodiverse than one based around exotics. As the harvesting method involves the selective removal of individual or small groups of trees rather than clear-felling, ground disturbance is minimised which in turn reduces runoff and soil erosion. Importantly, the forest remains a functional ecosystem despite occasional tree removal. As the forest ages the size structure of the timber trees becomes more complex. In turn with greater habitat complexity comes greater biodiversity.
Over time more specialised species of plants and animals will begin to colonise the forest especially those associated with aging trees (such as epiphytes), lower light levels, and decomposition. Often forest managers will deliberately retain fallen trees and dead standing trunks to enhance ecological networks based around fungal decomposition and to enhance habitat for hole-nesting birds and bats. In this way a close-to-nature forest operation will, over time, metamorphise from a plantation like structure to something functioning more like an old-growth forest.
