Wednesday, March 18, 2020
Pioneer Tree Species and Biological Forest Succession
Pioneer Tree Species and Biological Forest Succession Pioneer plant species are the first predictable seeders, adaptable to many conditions and the most vigorous flora to colonize disturbed or damaged ecosystems. These plants readily acclimate to bare soil, have the ability to grow and regenerate and respond vigorously on even the poorest soil sites and environmental conditions. Pioneer tree species are also known for their ability to readily seed or root sprout on bare soil and withstand the rigors of low moisture availability, full sunlight and high temperatures along with poorly available site nutrients. These are the plants, including trees, that you first see after a disturbance or fire in newly forming ecotones during field succession. These first tree colonizers become the initial forest tree component of a new forest. North American Pioneers Common pioneer tree species in North America: red cedar, alder, black locust, most pines and larches, yellow poplar, aspen, and many others. Many are valuable and are managed as even-aged stands, many are not desirable as a crop tree and removed for a more desired species. The Process of Forest Succession Biological succession and often-called ecological successionÃ is the process whereby disturbed existing forests regenerate or where fallow untended lands return to a forested condition. Primary succession is the ecological term where organisms are occupying a site for the first time (old fields, roadbeds, agricultural lands). Secondary succession is where organisms that were part of an earlier successional stage before a disturbance return (forest fire, logging, insect damage). The first plants to grow naturally in a burned or cleared area are usually weeds, shrubs or inferior scrubby trees. These plant species are often controlled or totally removed as defined in a prescribed forest management plan to prepare the area for higher quality tree regeneration. The Classification of Trees following the Pioneers It is important to know which trees will first attempt to cover the site. It is also important to know usually the most dominant tree species in the region that will eventually take over in the process of biological succession. Those trees that move on to occupy and become the main tree species are known as the climax forest community. The regions where these communities of tree species are dominant become the climax forest. Here are the major climax forest regions in North America: The Northern Boreal Coniferous Forest. This forest region is associated with the northern zone of North America, mostly in Canada.The Northern Hardwood Forest. This forest region is associated with the hardwood forests of the Northeastern United States and Eastern Canada.The Central Broadleaf Forest. This forest region is associated with the central broadleaf forests of the Central United States.The Southern Hardwood/Pine Forest. This forest region is associated with the Southern United States along the lower Atlantic through the Gulf coastal areas.The Rock Mountain Coniferous Forest. This forest region is associated with the mountain range from Mexico to Canada.The Pacific Coast Forest. This forest region is with the coniferous forest that hugs the Pacific coast of both the United States and Canada.