Fires of moderate severityoften resulted in stands with two or more age classes of trees (Agee1993~. Many of the hardwoods are able to send up vigorous, fast-growing sprouts from their roots. Scientists call this process ecological succession.Really, forests will build themselves, because the world is constantly undergoing change, or succession. Plants and animals resilient enough to first colonize such sites are the "base" community that kick starts the complex development of soil and refines the local climate. Harvest activities, especiallyclearcutting, generally leave a much less variable postdisturbance1 72Pacific Northwest ForestsSmall-scale disturbances in forests (e.g., gaps created by the loss ofone to a few trees) tend to facilitate the replacement of Douglas-fir byshade-tolerant species. This concept explains why your forest looks the way it currently does and how it will likely change in the future. The normal life span of the southern pines in this area is 80 to 120 years. programs over the past 75 years have been enor-mously successful in reducing the area burned each year, nationally andregionally (MacCleery 1995 ). Stop by, email, or call.During my experience as an ecologist I was lucky enough to see the stages of forest growth, but not everyone has the opportunity to see a forest grown from scratch. That in turn has led to more devastating fires and pestoutbreaks in recent years than likely occurred in the past when fuels andhost abundance were limiting factors (Anderson et al. With subsequentthinning, pine canopies are kept open by repeated low-intensity surfacefires. Forest succession is simply the succession or the orderly and predictable change in the dominant species of forest plants.
Within the next year or so, they are replaced by larger herbaceous species such as Queen Anne’s lace, asters and broom sedge. Where fires burn lessfrequently, fuels are distributed more continuously from forest floor tocanopy. Extensivestands of lodgepole pine characterize higher-elevation forests, while acomplex of Douglas-fir and ponderosa pine forests dominate at lowerelevations.Montana and Idaho forests dominated by Douglas-fir generally havelonger fire intervals than ponderosa pine forests. The French naturalist Adolphe Dureau de la Malle was the first to make use of the word succession concerning the vegetation development after forest clear-cutting. Before many plants can inhabit a rocky area, soil must be present. In reality this closed state is probably never realized, being prevented by disturbances caused by secondary environmental factors such … The intervals are considerably longer and lesspreclictable on the moist west slope of the Cascades. CAB International, Wallingford. The first stage-estabZishment is characterized by extensive seedling establishment and rapid growth, during which competitive interactions among individual plants are somewhat limited. The southern pine bark beetle, which in the mid-1970s aroused much concern in Durham and Orange counties, has probably always been a significant force in killing over-mature pines and allowing succession to proceed.
The first stage of forest succession is the grass, or plant stage, which occurs after land has been cleared due to natural events or otherwise.
ideal climax stage, the forest is closed, consisting of few species and is considered a less than optimal environment for human populations.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.This volume will be of interest to public officials, policymakers, the forest products industry, environmental advocates, researchers, and concerned residents.Forest Succession, Fire, and Landscape Dynamics7 79environment than do fires. 1994~. (ed.). Shade-tolerant trees may not becomesuccessfully established in forests with frequent ground fires (as inponderosa pine and Douglas-fir on drier sites).FIRE AND LANDSCAPE DYNAMICSAmong the various sources of natural disturbance, fire has been mostimportant in affecting the forested landscapes of the Pacific Northwest.The frequency and intensity of fire within the region varies considerablydepending on temperature and moisture conditions of the site, ignitionpatterns, and the characteristics of individual tree species and theirsusceptibility to fire (Agee 1981~. This change is made possible because plants are constantly competing with one another for sunlight, water, and nutrients. As it became increasingly difficult to eke out an existence, many farmers dropped their plows for good and moved into the growing cities to work. These sprouts can rapidly form another hardwood forest stand of about the same composition as the one removed. Only the hardiest of organisms can adapt at first.There was an error. But the direct effect of fire on fuels is highly variable.Repeated, low-intensity fires tend to produce fuel loads and structures(e.g., vertical stratification) that are not conducive to high-intensity,crown-killing fires. Sometime between 200 and 300 years ago the site of the Sunken Forest was an area of bare, windblown sand. Without intervention, fireswill burn up to natural boundaries, such as rivers; ridges; and low-fuelecosystems, such as rocky scree or feldfields.