Early impacts of harvesting and burning disturbances on vegetation communities in the Warra silvicultural systems trial, Tasmania, Australia

2011 ◽  
Vol 59 (8) ◽  
pp. 701 ◽  
Author(s):  
Mark G. Neyland ◽  
S. Jean Jarman

Impacts on the understorey vegetation of a range of silvicultural alternatives to clearfelling in lowland Eucalyptus obliqua wet forest were studied over a decade in the Warra silvicultural systems trial in southern Tasmania. The treatments were clearfell with understorey islands, patchfell, stripfell, dispersed retention, aggregated retention, and single-tree/small-group selection. High intensity burning, low intensity burning and no burning were variously applied as part of these treatments. Three understorey types were studied, including one wet sclerophyll community and two rainforest communities. Wherever burning occurred across the research trial, the regenerating vegetation was floristically wet sclerophyll with an incipient composition consistent with that of the pre-harvest wet sclerophyll community. Sites previously occupied by rainforest understoreys retained occasional rainforest elements, but the regeneration was overwhelmingly sclerophyll in nature. There were no consistent differences in the floristic composition of the regenerating vegetation, after burning or harvesting disturbance, that could be attributed to the silvicultural system. However, field observations and the results of a related, subsequent study suggest that, in designing silvicultural trials similar to the present one, close attention should be paid to the size of quadrats in relation to the level at which disturbance impacts are operating. The response of the vegetation at edges created by the treatments, and in the undisturbed forest beyond, supports the finding that edge effects on the vascular flora extend for less than 10 m into the undisturbed forest.

2021 ◽  
Vol 67 (No. 3) ◽  
pp. 101-112
Author(s):  
Javed Iqbal

Site conditions (topography, aspect, moisture availability, humus thickness, light exposure, and grazing activities) play a vital role in the germination and regeneration process. The research was conducted in the Himalayan moist temperate forest. The research site was divided based on the silvicultural system (group selection system and single-tree selection system) into 148 plots and 150 plots, respectively. The group selection system was examined on the site of 2 ha which was clear-felled under a project in the 1980's. The present study examined the impact of silvicultural systems on regeneration. The frequency table was used, and relative frequency was calculated for the species and silvicultural system, density per m2 was also calculated. Diversity indices were calculated through taxa, dominance, Simpson’s index, Shannon index, evenness, equitability, and fisher alpha. Ten taxa were found in both silvicultural systems, with individual repetition of 17 and 15 taxa, respectively. Group selection is more compact visibly as compared to the single-tree selection system. The single-tree selection system is more diversified in species composition, stand structure, moisture availability, and less humus availability. The study also highlights future predictions for the conservation of these forests, which are highly sensitive and a hotspot for wildlife and climate change phenomena. Silvicultural practices such as silvicultural system, cleaning, weeding, thinning operations are regularly practiced, which can reduce the negative impact on these productive forests.


2016 ◽  
Vol 46 (4) ◽  
pp. 499-507 ◽  
Author(s):  
Daniel M. Geleynse ◽  
Erica Nol ◽  
Dawn M. Burke ◽  
Ken A. Elliott

The Brown Creeper (Certhia americana Bonaparte, 1838) has been identified as one of the most sensitive passerines to partial forest harvest in North America. The effect of selection logging on Brown Creeper density, nest timing, nest survival, and nest and foraging site selection was examined in five silviculture treatments (intensive group selection, typical group selection, old single-tree selection, recent single-tree selection, and control forests) of Algonquin Provincial Park, Canada. As Brown Creeper nests under the bark of large, decaying trees, we hypothesized that Brown Creeper density, timing of breeding, nest survival, and nest and foraging site selection would be negatively affected by silviculture through the removal of large, decaying trees as part of providing safe conditions for loggers. We monitored 101 nests of Brown Creeper during the 2010 and 2011 breeding seasons, mapped territories to estimate density, and conducted foraging surveys. Brown Creeper density was reduced by about 42% in logged stands compared with control stands. Despite that, silviculture did not significantly alter timing of breeding or nest survival. However, the loss of large trees through partial harvesting meant that Brown Creeper nested closer to adjacent, small forested wetlands and often in balsam fir (Abies balsamea (L.) Mill.) in treated stands. In control stands, Brown Creeper nested further from forested wetlands, disproportionately in greater numbers in upland hardwoods, and preferentially in the bark of snags of yellow birch (Betula alleghaniensis Britton). The change in the species of tree used for nesting and the general forest type as a result of logging also resulted in consequences for the selection of foraging substrates. To maintain higher densities of Brown Creeper in logged stands in Algonquin Park, we recommend retaining larger diameter yellow birch, both snags and live trees, preferably within strategically located uncut reserves based on habitat supply planning, that maintains patches roughly the size of Brown Creeper territories (10 ha).


1993 ◽  
Vol 3 (1) ◽  
pp. 13 ◽  
Author(s):  
MD Cain

The effects of burning cycles and pine basal area levels were assessed on natural pine regeneration and hardwood development in uneven-aged stands of loblolly and shortleaf pines (Pinus taeda L. and P. echinata Mill.). The treatments included an unburned control and prescribed winter burns at 3-, 6-, and 9-yr intervals. Basal area treatments were 9, 14, 18, and 23 m2 ha-1 for the merchantable-pine component and were maintained on a 6-yr cutting cycle using single-tree selection. Ten years after the study was initiated, density and quadrat stocking of pine regeneration were negatively correlated with overstorey basal area. The 6-yr burning cycle had higher pine density and better quadrat stocking of pine regeneration compared with any other bum treatment mainly because the 6-yr burning cycle coincided with a bumper pine seedcrop and the 6-yr cutting cycle. Recurring fires tended to result in reduced size of hardwood competition but had less impact on hardwood density. When considering a prescribed burning program in uneven-aged stands of loblolly and shortleaf pines, more attention should be given to density, quadrat stocking, and size of established pine regeneration and to expected seedcrops rather than to the prosecution of rigid burning schedules.


Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 141 ◽  
Author(s):  
Harold M. Armleder ◽  
Susan K. Stevenson

Even-aged forest management using the clearcutting silvicultural system as it is currently applied threatens mountain caribou habitat in British Columbia. Since neither complete preservation nor maximum development of timber resources are socially acceptable alternatives, forest managers are anxious to find integrated management options. We describe alternative silvicultural systems currently being tested, including single-tree and group selection. All the treatments have the goal of periodically extracting viable timber volumes while perpetually retaining stand characteristics necessary for caribou. The effects of these logging prescriptions on lichen biomass and growth rates are being tested. Alternative silvicultural systems may become part of a larger strategy to maintain caribou habitat in managed forests.


1994 ◽  
Vol 10 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Johan L. C. H. Van Valkenburg ◽  
Pieter Ketner

ABSTRACTThis paper examines the floristic changes that occur following human disturbance in mid-montane forest in the Wau area in Papua New Guinea. The study was restricted to a 1600–2400 m altitudinal range on Mt Kaindi, with disturbed forest, and Mt Missim, with undisturbed forest. Special attention was given to the status of Nothofagus pullei which is locally dominant on Mt Kaindi.A major change in floristic composition was observed between 1800 and 2000 m. The abundance and species composition of ferns and mosses above 2000 m characterizes the floristic differences. Nothofagus pullei was found to be a pioneer species with a long life-span, one which does not regenerate under its own cover. There were no other important floristic differences between Notho-fagus-dominated forest and mixed mid-montane forest. Nothofagus pullei locally dominates the canopy and thereby suppresses the growth of other trees.


2002 ◽  
Vol 17 (4) ◽  
pp. 202-206 ◽  
Author(s):  
John R. Moore ◽  
Douglas A. Maguire ◽  
David L. Phillips ◽  
Charles B. Halpern

Abstract An inventory of fresh logging wounds from treatment implementation was performed in a regional green-tree retention experiment in Oregon and Washington. The DEMO (Demonstration of Ecosystem Management Options) study contains six treatments replicated in six blocks: (1) 100% retention (control), (2) 75% aggregated retention, (3) 40% dispersed retention, (4) 40% aggregated retention, (5) 15% dispersed retention, and (6) 15% aggregated retention. Over all blocks and treatments, Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) comprised 74.9% of all measured trees, and the proportion of trees damaged was similar for both species. Suppressed trees tended to be more susceptible to damage than were trees in other crown classes. A greater proportion of trees in the dispersed retention treatments were damaged than in the aggregated treatments. Only in the two dispersed retention treatments were levels of damage significantly different from the control (P < 0.05). The greatest proportion of damaged trees occurred in the 15% dispersed retention treatment and was likely due to the wider dispersion and higher intensity of felling and yarding operations associated with this treatment. The pattern of damage across treatments was similar for both small (≤ 25 cm dbh) and large (> 25 cm dbh) trees. Some evidence was also found that the sites with gentler slopes had less damage than those with steeper topography. Probable effects of wounds on future growth and tree health could not be inferred as no data were collected on wound size or height. However, it is expected that the future incidence of stem rot and growth reduction will be greatest in the dispersed retention treatments. West. J. Appl. For. 17(4):202–206.


2010 ◽  
Vol 86 (1) ◽  
pp. 100-109 ◽  
Author(s):  
Karla J. Falk ◽  
Ken A. Elliott ◽  
Dawn M. Burke ◽  
Erica Nol

We evaluated the immediate effects of group selection harvesting on the establishment of yellow birch (Betula alleghaniensis Britt.) and black cherry (Prunus serotina Ehrh.) seedlings in maple-dominated hardwood stands of Algonquin Provincial Park, Ontario. Group selection gaps were compared to single-tree selection cutting and uncut reference stands pre-harvest and one growing season post-harvest using a before-after-control-impact (BACI) design. The percent cover of yellow birch seedlings increased significantly more in gaps than in single-tree selection and reference plots. Black cherry seedling cover increased significantly more in gaps than in reference plots, but increased at a similar rate in gaps and single-tree selection plots. Increased soil exposure and closer seed trees resulted in increased yellow birch recruitment when harvesting occurred in the late-summer-fall. These factors had little influence on yellow birch recruitment when harvesting occurred in the winter. The proportion of black cherry in the stand overstory had the greatest influence on black cherry recruitment; however, the uneven distribution of black cherry between stands may have precluded our ability to reliably test the influence of other factors. Concomitant increases in potential competitors such as wild red raspberry (Rubus strigosus Michx.) and sedges (Carex spp.) and the continued dominance of sugar maple (Acer saccharum Marsh) in gap openings may limit yellow birch and black cherry regeneration in successive growing seasons. While continued monitoring is required, our short-term results demonstrate that fall harvesting with group selection is effective at stimulating natural regeneration of yellow birch and black cherry. Key words: yellow birch, black cherry, seedling recruitment, group selection, single-tree selection, mid-tolerant, shadeintolerant


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