http://cfs.nrcan.gc.ca/subjects/read/3?sort=title&format=citation Publications - Forest Ecology and Site Classification en-ca 2012-07-12 12:40:22 MST 2012-07-12 12:40:22 MST webmaster@nofc.cfs.nrcan.gc.ca http://cfs.nrcan.gc.ca/publications?id=33918 Thu, 12 Jul 2012 http://cfs.nrcan.gc.ca/publications?id=33918 http://cfs.nrcan.gc.ca/publications?id=25710 Old-growth forests make up a substantial proportion of the forest mosaic in the Clay Belt region of Ontario and Quebec, Canada, despite fire cycles that are presumed to be relatively short. Two hypotheses have been suggested as explanations for this phenomenon: (1) the old-growth forests in question are located on sites that are protected from fire or (2) the fire hazard is just as great there as elsewhere, and that part of the mosaic is simply the tail of the distribution, having been spared from fire merely by chance. The tree-ring method has proven inadequate as a means of determining the date of the most recent fire in these old-growth forests, as the time that has elapsed since that date probably exceeds the age of the oldest trees. Accordingly, a paleoecological study was conducted with a view to determining the date of the last fire in these forests. Charcoal horizons were located and radiocarbon dated in six old-growth forests. The possibility that these forests have never burned at all is ruled out by the fact that macroscopic charcoal fragments were found at all sites. The proximity of potential firebreaks has a significant influence in the survival model, suggesting fire-cycle heterogeneity throughout the landscape. However, the proportion of old-growth forests observed is in agreement with what would be expected assuming that fire hazard is independent of stand age. Old-growth stands could thus be incorporated into natural disturbance based management, although the great variability of the intervals between catastrophic disturbances should be carefully considered. Wed, 21 Sep 2005 http://cfs.nrcan.gc.ca/publications?id=25710 http://cfs.nrcan.gc.ca/publications?id=21717 Mon, 02 Jun 2003 http://cfs.nrcan.gc.ca/publications?id=21717 http://cfs.nrcan.gc.ca/publications?id=21745 Tue, 03 Jun 2003 http://cfs.nrcan.gc.ca/publications?id=21745 http://cfs.nrcan.gc.ca/publications?id=20477 Thu, 08 Aug 2002 http://cfs.nrcan.gc.ca/publications?id=20477 http://cfs.nrcan.gc.ca/publications?id=18943 Sat, 01 Dec 2001 http://cfs.nrcan.gc.ca/publications?id=18943 http://cfs.nrcan.gc.ca/publications?id=18879 Wed, 28 Nov 2001 http://cfs.nrcan.gc.ca/publications?id=18879 http://cfs.nrcan.gc.ca/publications?id=4830 Fines from log sortyards (<5 cm) present a disposal problem and a utilization potential. We examined <3 mm and 3-13 mm size fractions of sortyard wastes near Vernon, B.C., and <16 mm fines from mechanical separator trials near Vernon and Port Alberni. To facilitate analysis, the 3-13 mm samples were separated by floatation and hand-sorting into rock fragments and an organic fraction. The 3-13 mm organic fractions and <16 mm separates were still too high in mineral content to be used for fuel. The organic fingerprints obtained from solid-state 13C nuclear magnetic resonance spectroscopy (CPMAS NMR) were similar to those for decomposing wood or forest floor and did not indicate high bark content. The <3 mm fraction was lower in organic matter with C-13 NMR spectra similar to those found for mineral soil size fractions. These materials should be suitable as organic amendments for site reclamation or composting with due regard for their high C/N ratios and the naturally slow rate of wood decomposition. Sat, 26 Aug 2000 http://cfs.nrcan.gc.ca/publications?id=4830 http://cfs.nrcan.gc.ca/publications?id=4876 Proximate analysis is often used in decomposition studies to characterize the organic components of foliar litter. The percent weight residue remaining after extraction by nonpolar and polar solvents and H2SO4 hydrolysis (Klason lignin, KL) is commonly used as a measure of litter quality and a modelling parameter. While KL is associated with resistance to decay, its nature is not well understood and it has long been suspected that it incorporates nonlignin components. We used solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to characterize litter, extracted residue, and the KL fraction of five species. NMR shows that cutin and condensed tannin are both significant components of litter and its extraction residues, in addition to lignin and carbohydrate. Hydrolysis with H2SO4 removes carbohydrates and amino acids, leaving the KL fraction derived from cutin, tannin, and lignin. Tannin retention in KL was also demonstrated by a hydrolysis study of purified tannins and a brown-rot lignin, using both NMR and the proanthocyanidin assay for condensed tannins. Although the NMR results are qualitative at this stage, it is clear that KL has limited use as a parameter controlling litter decomposition, and that other biopolymers should not be ignored in conceptual models, chemical analysis, and experimental design. Sat, 26 Aug 2000 http://cfs.nrcan.gc.ca/publications?id=4876 http://cfs.nrcan.gc.ca/publications?id=18910 Thu, 29 Nov 2001 http://cfs.nrcan.gc.ca/publications?id=18910 http://cfs.nrcan.gc.ca/publications?id=2525 Sat, 26 Aug 2000 http://cfs.nrcan.gc.ca/publications?id=2525 http://cfs.nrcan.gc.ca/publications?id=19120 Tue, 18 Dec 2001 http://cfs.nrcan.gc.ca/publications?id=19120 http://cfs.nrcan.gc.ca/publications?id=18664 The Carbon Budget Model of the Canadian Forest Sector (CBM–CFS2) is a framework for the dynamic accounting of carbon pools and fluxes in Canada’s forest ecosystems and the forest product sector. The model structure, assumptions, and supporting databases are described. The model has been applied to estimate net ecosystem carbon fluxes for Canada’s 404 Mha forest area for the period 1920–1989. Changes in disturbance regimes have affected the forest age class structure and increased the average forest age during the period 1920–1979. The resulting changes in dead organic matter and biomass carbon during this period were estimated with the model. In the last decade of the analysis, large increases in disturbances, primarily fire and insect damage, have resulted in a reduction in ecosystem carbon storage. The estimates of biomass pool sizes obtained are consistent with those of other studies, while dead organic matter carbon pool estimates remain somewhat uncertain. Sensitivity analysis of several sources of uncertainty indicate that the pattern of net changes in ecosystem carbon pools over the 70-yr period was hardly affected and that the numerical estimates changed by >15%. Thu, 25 Oct 2001 http://cfs.nrcan.gc.ca/publications?id=18664 http://cfs.nrcan.gc.ca/publications?id=29825 Design-based estimators of the sampling variance for apparent (S0 = observed) and predicted species richness have been lacking. A balanced repeated replication (BRR) estimator is proposed and recommended for S0. Good performance of the estimators is demonstrated in two contrasting examples with Monte Carlo (MC) simulations of simple random sampling with fixed area quadrats (plots) for estimating forest tree species richness. Chao and Lee's estimator of species richness was used. In BRR a set of half-samples forming an orthogonal design with respect to the inclusion/exclusion of sample records is used to produce estimates from the observed half-sample and models for the effect of data-splitting. BRR estimates of the sampling variance of S0 were close to the MC estimates in the examples from eastern Canada (PROV) and the Barro Colorado Island (BCI) and clearly superior to naive model-based estimates. BRR estimates were generally close to their MC counterparts, but in BCI a bias of approximately -10% was seen in small samples (n = 24). BRR estimates of sampling variance in PROV were close to the MC estimates for n = 60. With larger sample sizes the BRR estimates drifted toward values obtained with Chao and Lee's model-based variance estimator. In BCI the opposite was true. Fri, 24 Jul 2009 http://cfs.nrcan.gc.ca/publications?id=29825 http://cfs.nrcan.gc.ca/publications?id=21403 Thu, 03 Apr 2003 http://cfs.nrcan.gc.ca/publications?id=21403 http://cfs.nrcan.gc.ca/publications?id=25959 Significance levels of the popular Wald's Chi-squared statistic for simple goodness-of-fit (GOF) tests under one-stage cluster sampling are often unreliable. A large number of alternatives to Wald's GOF test with Type-I error rates more closely matching the nominal level of significance have been proposed but not yet found their way into applied statistics. Type-I error rates with Wald's test-statistic in cluster sampling from 10 actual forest cover-type maps from 5 sites and 81 sample designs are compared to the error rates of 11 alternatives. The effects of site, sampling design, evenness of cover-type class proportions, and intra-cluster correlation on Type-I error rates are quantified with logistic regressions for Wald's statistic and five promising alternatives. Our proposed second-order bias correction of Finney's [Finney, D.J., 1971. Probit Analysis, vol. 3. Cambridge University Press, p. 350] and Brier's [Brier, S.S., 1980. Analysis of contingency tables under cluster sampling. Biometrika 67, 591–596] method of moments correction of Pearson's Chi-squared test statistic emerged as the overall best alternative in this study. It was the least sensitive to design and cluster effects. Test power was investigated for the alternative simple hypothesis of equality of cover-type proportions in two site-specific maps. The proposed alternative test statistic had slightly (3%) less power than Wald's test for designs with a power of 80% or greater, yet a consistently better odds ratio of a correct test decision. Tue, 10 Jan 2006 http://cfs.nrcan.gc.ca/publications?id=25959 http://cfs.nrcan.gc.ca/publications?id=21398 Thu, 03 Apr 2003 http://cfs.nrcan.gc.ca/publications?id=21398 http://cfs.nrcan.gc.ca/publications?id=30163 Thu, 15 Oct 2009 http://cfs.nrcan.gc.ca/publications?id=30163 http://cfs.nrcan.gc.ca/publications?id=7056 Fri, 21 Jul 2000 http://cfs.nrcan.gc.ca/publications?id=7056 http://cfs.nrcan.gc.ca/publications?id=11226 Tue, 22 Aug 2000 http://cfs.nrcan.gc.ca/publications?id=11226 http://cfs.nrcan.gc.ca/publications?id=33928 Thu, 12 Jul 2012 http://cfs.nrcan.gc.ca/publications?id=33928 http://cfs.nrcan.gc.ca/publications?id=22484 Tue, 22 Jul 2003 http://cfs.nrcan.gc.ca/publications?id=22484 http://cfs.nrcan.gc.ca/publications?id=33917 Thu, 12 Jul 2012 http://cfs.nrcan.gc.ca/publications?id=33917 http://cfs.nrcan.gc.ca/publications?id=33915 Thu, 12 Jul 2012 http://cfs.nrcan.gc.ca/publications?id=33915 http://cfs.nrcan.gc.ca/publications?id=23753 Tue, 27 Jan 2004 http://cfs.nrcan.gc.ca/publications?id=23753