Structural differences between forests regenerating following spruce budworm defoliation and clear-cut harvesting: implications for marten

2000 ◽  
Vol 30 (12) ◽  
pp. 1965-1972 ◽  
Author(s):  
David C Payer ◽  
Daniel J Harrison

American marten (Martes americana Turton) avoid recent clearcuts when establishing territories but do not avoid similarly aged stands with a history of extensive tree mortality caused by the eastern spruce budworm (Choristoneura fumiferana Clem.). We quantified differences in overstory vegetation, understory vegetation, and coarse woody debris between stands that were clear-cut or defoliated by spruce budworms 10-20 years prior to our study. Our objectives were to identify habitat features with functional significance for marten that were lacking in managed stands and to propose goals for silvicultural practices that more closely resemble a natural disturbance (insect defoliation), thus improving habitat quality for marten. In contrast to regenerating clearcuts, defoliated stands had greater volumes of snags, downed logs, and root masses and included taller trees. Although live-tree basal area was similar between stand types, our results suggest that vertical structure provided by large snags can offset limited availability of live trees for marten, particularly where coarse woody debris and understory vegetation are plentiful. In stands under even-aged management, habitat quality for marten may be enhanced by retention of >18 m2/ha cull trees and snags. Uneven-aged silvicultural systems, which more closely mimic natural disturbance by defoliating insects, may have particular promise for maintaining marten habitat.

2007 ◽  
Vol 37 (9) ◽  
pp. 1525-1533 ◽  
Author(s):  
B. D. Harvey ◽  
S. Brais

In the winter of 1998–1999, two partial harvesting treatments that removed 33% (1/3) and 61% (2/3) of stand basal area were applied to even-aged trembling aspen ( Populus tremuloides Michx.) stands and compared with unharvested control stands. Stands in the 1/3 treatment were low thinned, while stands in the 2/3 removal were crown thinned. Coarse woody debris dynamics were assessed during the following 6 years by means of permanent sampling plots and downed wood inventories. Between 1999 and 2004, tree mortality was, respectively, 18%, 17%, and 32% in control stands and 1/3 and 2/3 harvesting treatments. Although total snag density was similar between controls and partial cutting treatments, total snag basal area was significantly higher in controls in 2004. Between 1999 and 2004, net change in aspen snag density was positive for controls and negative for both partial cutting treatments. Partial cutting also exacerbated mortality of small-diameter white birch ( Betula papyrifera Marsh.). Downed wood volume increased by 35 m3·ha–1 in controls and by 25 m3·ha–1 in the 2/3 harvesting treatment, while it decreased by 7 m3·ha–1 in the 1/3 harvesting treatment. Coarse woody debris goals can be established in silviculture prescriptions; type, timing, and intensity of partial cutting are crucial to the outcome.


1983 ◽  
Vol 59 (6) ◽  
pp. 294-297 ◽  
Author(s):  
J. R. Blais

Forest managers have expressed the need for guidelines that would predict, up to 5 years, the annual spruce budworm damage on a stand basis. Reasons why reliable prediction is generally not possible are discussed. It is suggested that long-term management programs, that would take into consideration periodic losses resulting from recurring budworm outbreaks and that would be based on regional differences in the vulnerability of fir-spruce stands, should be implemented. Key words: Spruce budworm, Choristoneura fumiferana; forest management; tree mortality; defoliation; stand vulnerability, balsam fir, Abies balsamea.


1994 ◽  
Vol 24 (10) ◽  
pp. 1989-1996 ◽  
Author(s):  
Glenn H. Stewart ◽  
Larry E. Burrows

The volume, biomass, and carbon and nitrogen content of coarse woody debris were measured on three 1-ha reference plots in old-growth Nothofagusfusca (Hook. f.) Oerst.–Nothofagusmenziesii (Hook. f.) Oerst. forest on the South Island of New Zealand. Two decay sequences for logs and one for standing dead trees (snags) were recognised from two-way indicator species analysis (TWINSPAN) of up to 30 variables related to physical characteristics and structural integrity. Wood volume (up to 800 m3•ha−1) and biomass were high (up to 300 Mg•ha−1), and the inside-out decay sequence from heartwood to sapwood was unusual compared with that of other temperate hardwood forests. Coarse woody debris represented significant carbon and nitrogen pools, with ca. 150 Mg•ha−1 and 370 kg•ha−1, respectively, in one stand. The coarse woody debris component of these broad-leaved evergreen hardwood forests was much higher than that reported for other temperate hardwood forests and approaches that of many northern hemisphere conifer forests. The large coarse woody debris pools are discussed in relation to live stand biomass, natural disturbances and tree mortality, and decomposition processes.


1984 ◽  
Vol 60 (5) ◽  
pp. 273-279 ◽  
Author(s):  
David A. MacLean

Effects of spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks on the productivity and stability of forests in eastern Canada are reviewed and discussed. Defoliation results in reduced growth of trees, widespread tree mortality, and loss of wood production, and thereby causes major forest management problems. At present, the only feasible method for limiting damage and losses from budworm outbreaks over large areas is to apply chemical or biological insecticides periodically to kill larvae and protect the forest from defoliation and tree mortality. Although budworm outbreaks definitely disrupt the wood-producing capacity of forests (or the short-term "stability of forests for human usage"), in terms of overall ecological stability, outbreaks apparently act as a cycling mechanism that allows advance fir-spruce regeneration to succeed the fir-spruce overstory.


2020 ◽  
Vol 29 (3) ◽  
pp. e021
Author(s):  
Ovidiu Copoț ◽  
Cătălin Tănase

Aim of the study: The main objective of this study was to find the factors which best explains the wood-inhabiting fungal species’ richness in beech and oak-dominated forests.Area of study: We focused on broadleaved and mixed forests found in Northeastern Romania.Materials and methods: 59 plots were randomly set up in broadleaved and mixed forest stands, in which vegetation structure, composition, and topoclimatic factors were quantified along with wood-inhabiting fungal richness. Generalized linear models were used to characterize relationship between fungal diversity and biotic and abiotic factors.Main results: 374 taxa were identified, with numerous species found to cohabitate, the highest sharing being between Fine Woody Debris and Downed Coarse Woody Debris. The best predictors of total diversity were related to the substrate, management, stand structure, and macroclimate. Higher volumes of logs and large branches in various decay stages increased fungal richness. The same effect was found in diverse forests, with large snags. Macroclimate and topoclimate positively influenced diversity, through De Martonne Aridity Index and snow cover length, both indicating macrofungi preferences for higher moisture of substrate. Silvicultural interventions had an ambivalent effect to fungal diversity, phenomenon observed through stump numbers and proportion.Research highlights: Particular environmental characteristics proved significantly important in explaining different wood-inhabiting fungal richness patterns. Substrate-related variables were the most common ones found, but they were closely linked to climate and forest stand variables.Keywords: Wood-inhabiting fungi; oak, beech and coniferous forests; substrate diversity; dead wood types; coarse woody debris; fine woody debris; climatic variables.Abbreviations used:ALT, elevation; ASPI, Aspect Index; BIO1, mean annual temperature; BIO4, temperature seasonality; BIO7, annual temperature range; BIO12, annual precipitation; BIO15, precipitation seasonality; CWD, coarse woody debris; DBH, diameter at breast height; DCWD, downed coarse woody debris; DCWD_DECAY, DCWD decay diversity; DCWD_DIV, DCWD taxonomic diversity; DCWD_SV, surface-volume ratio of DCWD; DCWD_VOL, DCWD volume; DMAI, De Martonne Aridity Index; DMAI_AU, Autumn DMAI; DMAI_SP, Spring DMAI; DMAI_SU, Summer DMAI; DMAI_WI, Winter DMAI; FAI, Forestry Aridity Index; FWD, fine woody debris; L_SNAG_BA, large snag basal area; OLD_BA, basal area of old trees; POI, Positive Openness Index; RAI, Recent Activity Index; SCL, snow cover length; SLOPE, slope; SNAG_N, snag density; STUMP_N, stump density; TPI, Topographic Position Index; TREE_BA, mean basal area of trees; TREE_DIV, tree' Shannon diversity.


2016 ◽  
Vol 12 (9) ◽  
pp. 69
Author(s):  
Carlos Belezaca Pinargote ◽  
Darwin Salvatierra Piloso ◽  
Diana Delgado Campusano ◽  
Roberto Godoy Bórquez ◽  
Eduardo Valenzuela Flores ◽  
...  

Coarse woody debris (CWD) are the necromass in wooded environments and comply with various ecosystems functions, such as seedling nursery, habitat other organisms, store carbon (C) and nutrients, etc.. Volume, necromass, and decay states of CWD dead in an old-growth temperate (OGTF) forest in Puyehue National Park, South-Central Chile were evaluated. In 10 plots of 900 m2 CWD was quantified (≥ 10 cm diameter), whose necromass classified using a scale of five categories/stages of decay, necromass (1 = lowest and 5 = highest degradation). The average forest density was 299 trees ha-1, 112 m2 ha-1 of basal area, and 2.395 m3 of stem volume. The upper arboreal stratum was dominated by N. betuloides. The greatest amount of CWD belonged to N. betuloides (95,2%), where logs (52,7%) and branches (35%), plant structures were present in greater numbers. The bulk of necromass found in advanced states of decomposition (level 4 and 5) with 56,5% and 34,1%, respectively. It was determined that the CWD volume was 632 m3 ha-1, representing a necromass of 321.5 Mg ha- 1. These results demonstrate that the old-growth temperate forests of southern Chile are significant reserves of coarse woody debris, which contributes to the biogeochemistry of these complex and remote ecosystems.


2021 ◽  
Vol 4 ◽  
Author(s):  
Jeffrey Opoku-Nyame ◽  
Alain Leduc ◽  
Nicole J. Fenton

Clear cut harvest simplifies and eliminates old growth forest structure, negatively impacting biodiversity. Partial cut harvest has been hypothesized (1) to have less impact on biodiversity than clear cut harvest, and (2) to encourage old growth forest structures. Long-term studies are required to test this hypothesis as most studies are conducted soon after harvest. Using epixylic bryophytes as indicators, this study addresses this knowledge gap. Fourteen years after harvest, we examined changes in epixylic bryophyte community composition richness and traits, and their microhabitats (coarse woody debris characteristics and microclimate) along an unharvested, partial cuts and clear cuts harvest treatment in 30 permanent plots established in the boreal black spruce (Picea mariana) forests of northwestern Quebec, Canada. Our results were compared to those of an initial post-harvest study (year 5) and to a chronosequence of old growth forests to examine species changes over time and the similarity of bryophyte communities in partial cut and old growth forests. Coarse woody debris (CWD) volume by decay class varied among harvest treatments with partial cuts and clear cuts recording lower volumes of early decay CWD. The epixylic community was richer in partial cuts than in mature unharvested forests and clear cuts. In addition, species richness and overall abundance doubled in partial and clear cuts between years 5 and 14. Species composition also differed among treatments between years 5 and 14. Furthermore, conditions in partial cut stands supported small, drought sensitive, and old growth confined species that are threatened by conditions in clear cut stands. Lastly, over time, species composition in partial cuts became more similar to old growth forests. Partial cuts reduced harvest impacts by continuing to provide favorable microhabitat conditions that support epixylic bryophytes. Also, partial cut harvest has the potential to encourage old growth species assemblages, which has been a major concern for biodiversity conservation in managed forest landscapes. Our findings support the promotion of partial cut harvest as an effective strategy to achieve species and habitat conservation goals.


2010 ◽  
Vol 25 (4) ◽  
pp. 176-180 ◽  
Author(s):  
David Azuma

Abstract Forest Inventory and Analysis data were used to investigate the effects of a severe western spruce budworm outbreak on the dead wood component of forests in 11 counties of eastern Oregon for two time periods. The ownership and the level of damage (as assessed by aerial surveys) affected the resulting down woody material and standing dead trees. The pattern of coarse woody debris with respect to ownership and management intensity remained consistent into the next 10-year period. Harvesting tended to lower the amount of coarse woody debris on private forests. Federally managed forests had more standing dead trees than private lands, with more in the reserved than nonreserved areas. There was a reduction in the number of standing dead trees between the two periods.


1996 ◽  
Vol 72 (4) ◽  
pp. 393-398 ◽  
Author(s):  
Éric Bauce

Field rearing experiments of spruce budworm, Choristoneura fumiferana (Clem.), were conducted in conjunction with foliar chemical analyses, one and two years after a commercial thinning (removal of 25% stand basal area) in a 50-year-old balsam fir, Abies balsamea (L.) Mill., stand. The first year after thinning, spruce budworm larvae reared on the residual trees developed five days faster and removed 43% more foliage than those reared on control trees, but in the second year they developed two days faster and removed 37% more foliage. The increase in larval development rate was related to an increase in foliar soluble sugars while a reduction in foliar monoterpenes caused by the thinning apparently accounted for the greater amount of foliage ingested by the larvae. The first year after thinning, trees were more vulnerable to spruce budworm because there was no increase in foliage production and the trees were more heavily defoliated. However, in the second year trees were less vulnerable to the insect because there was an increase in foliage production that exceeded the increase in defoliation, hence a net gain in foliage. Results from this study showed that commercial thinning could reduce the vulnerability of balsam fir trees to spruce budworm if thinning is conducted two years prior to budworm outbreak, but the same silvicultural procedure could increase the vulnerability to the insect if it is conducted during an outbreak. Key words: spruce budworm, balsam fir, chemistry, thinning, defoliation


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