Attributes and indicators of old-growth and successional Douglas-fir forests on Vancouver Island

2003 ◽  
Vol 11 (S1) ◽  
pp. S187-S204 ◽  
Author(s):  
J A Trofymow ◽  
J Addison ◽  
B A Blackwell ◽  
F He ◽  
C A Preston ◽  
...  
Keyword(s):  
Species Abundance ◽  
Vancouver Island ◽  
Douglas Fir ◽  
Forest Area ◽  
Stand Development ◽  
Managed Forest ◽  
Old Growth ◽  
Data Set ◽  
Forestry Practices ◽  
Old Growth Forest

The Douglas-fir forests of coastal British Columbia are within the most heavily modified forest ecosystem types in coastal BC and local land managers are developing new forestry practices to retain elements of old growth within the managed forest area. To determine how successful these practices are requires the selection and monitoring of appropriate attributes and knowledge on how they change with stand development. In this paper we summarize previously published results from an extensive data set on four Douglas-fir dominated sites located on eastern Vancouver Island. Data were collected as part of the Coastal Forest Chronosequences project which was addressing questions on (1) how does conversion to managed forests impact species and forest structural diversity and (2) how does this diversity recover in older second-growth stands. Each site contained four stands, a postharvest chronosequence: regeneration (R, 5–10 years), immature (I, 25–45 years), and maturing (M, 75–95 years) stands, and an old growth (O, >240 years) control stand. Over 20 attributes are summarized including structural attributes, and at three sites, detailed biodiversity and process attributes. All old-growth plots exceeded the minimum age criteria and some but not all of the minimum structural attribute criteria for old-growth Douglas-fir forests in the US Pacific Northwest, reflecting regional or site type differences. Most structural attributes showed their greatest change within the first 100 years, although older stands (M and O) still differed based on tree and snag sizes and tree mass or basal area. Most species abundance and richness attributes and process attributes clearly differentiated R from the forested stages but were of less value for differentiating among older (M and O) stands. Arboreal lichen abundance and species richness; the abundance of cryptogams, achlorophyllus plants, litter collembola, and specific species of fungi and carabids; litter fall and gap fraction were the exception, these attributes clearly differentiating M from O stands. In postharvest stands, the overall pattern of change with succession for most attributes, as inferred from the chronosequence, was confirmed to be very different from a previously published conceptual model for post-fire succession. Compared to the post-fire model, the greatest changes in the postharvest stands occurred early in stand development, associated with canopy closure. Although stand structural attributes can clearly be used to distinguish old-growth features in managed forest stands, none-the-less it is important to monitor and demonstrate, at least for a selection of nonstructural attributes, that forestry practices are effective in maintaining biodiversity and associated processes of old-growth forests in the managed forest area. Key words: old-growth forest, succession, Douglas-fir forest, criteria and indicators, biodiversity, managed forest.

Analysis of “Don't Know” Responses to Referendum Contingent Valuation Questions

1998 ◽  
Vol 27 (2) ◽  
pp. 218-230 ◽  
Author(s):  
Michel K. Haener ◽  
Wiktor L. Adamowicz
Keyword(s):  
Contingent Valuation ◽  
Old Growth ◽  
Data Set ◽  
Old Growth Forest ◽  
Don't Know Responses ◽  
Insight Into ◽  
Forest Valuation

This paper considers the treatment of “don't know” (DK) responses to referendum contingent valuation questions. The determinants of DK responses are empirically analyzed using a data set from a survey of old growth forest valuation. It is found that DK respondents possess unique characteristics that differentiate them from Yes and No respondents. These findings do not support the most common treatments of DK responses that are currently used. Responses to an open-ended question included in the survey are used to provide further insight into the preferences of DK respondents.

Diversity of ectomycorrhizae on experimentally planted Douglas-fir seedlings in variable retention forestry sites on southern Vancouver Island

2004 ◽  
Vol 82 (11) ◽  
pp. 1671-1681 ◽  
Author(s):  
R A Outerbridge ◽  
J A Trofymow
Keyword(s):  
Root Colonization ◽  
Distance Effect ◽  
Vancouver Island ◽  
Douglas Fir ◽  
Stand Age ◽  
Mature Trees ◽  
Old Growth ◽  
Variable Retention ◽  
Second Growth ◽  
Retention Forestry

Studies were done on Vancouver Island of ectomycorrhizal (EM) communities at four distances (5–45 m) from isolated forest patches in three second-growth (SG) and three old-growth (OG) Douglas-fir sites subject to variable retention harvesting. We tested the hypothesis that retention of mature trees enhances colonization and diversity of EM fungi on seedlings planted in adjacent areas. In total 41 EM morphotypes were described, with mean diversity of 3.47 morphotypes and root colonization of 62% per seedling. Overall, root colonization declined with distance (72% at 5 m vs. 52% at 45 m), as did EM diversity (4.7 at 5 m vs. 2.9 at 45 m). For individual sites, the distance effect was significant for root colonization at four sites and for EM diversity at three to four sites. This suggests that variable retention is important for the recovery of ectomycorrhizal biota in harvested sites. Seedling root colonization was significantly lower in SG sites than in OG sites. Though EM diversity did not differ with stand age, OG sites had potentially more total (34) and unique (14) EM morphotypes than did SG sites (total 27, unique 7). Differences with stand age might be related to the relative abilities of EM fungi to disperse to regenerating second-growth forests.Key words: variable retention silviculture, ectomycorrhizae ecology, Douglas-fir seedlings, old growth, second-growth forests.

scholarly journals Bird Occupancy of a Neotropical Forest Fragment Is Mostly Stable over 17 Years but Influenced by Forest Age

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 50
Author(s):  
Marconi Campos-Cerqueira ◽  
W. Douglas Robinson ◽  
Gabriel Augusto Leite ◽  
T. Mitchell Aide
Keyword(s):  
Bird Species ◽  
Barro Colorado Island ◽  
Tropical Species ◽  
Forest Age ◽  
Forest Fragment ◽  
Long Term Effects ◽  
Old Growth ◽  
Data Set ◽  
Old Growth Forest

The effects of forest degradation, fragmentation, and climate change occur over long time periods, yet relatively few data are available to evaluate the long-term effects of these disturbances on tropical species occurrence. Here, we quantified changes in occupancy of 50 bird species over 17 years on Barro Colorado Island (BCI), Panama, a model system for the long-term effects of habitat fragmentation. The historical data set (2002–2005) was based on point counts, whereas the contemporary data set (2018) was based on acoustic monitoring. For most species, there was no significant change in occupancy; however, the occupancy of four species (Tinamus major, Polioptila plumbea, Myiarchus tuberculifer, and Ceratopipra mentalis) increased significantly, and the occupancy of three species (Saltator grossus, Melanerpes pucherani, and Cyanoloxia cyanoides) decreased significantly. Forest age explained the majority of occupancy variation and affected the occupancy of more bird species than survey period or elevation. Approximately 50% of the species seem to favor old-growth forest, and 15 species (30%) had a significantly higher occupancy in old-growth forest sites. Elevation had no significant impact on the occupancy of the majority of bird species. Although BCI has been a protected reserve for approximately 100 years, land-use legacies (i.e., forest age) continue to influence bird distribution.

The effect of soil disturbance on growth and ectomycorrhizae of Douglas-fir and western hemlock seedlings: a greenhouse bioassay

1982 ◽  
Vol 12 (2) ◽  
pp. 343-353 ◽  
Author(s):  
M. Meyer Schoenberger ◽  
D. A. Perry
Keyword(s):  
Soil Disturbance ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Root Tips ◽  
Old Growth ◽  
Clear Cut ◽  
Old Growth Forest ◽  
Litter Leachate ◽  
Oregon Cascades ◽  
Tip Formation

In a greenhouse bioassay of soils from the central Oregon Cascades, Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings had the most total and ectomycorrhizal root tips when grown in soil from an unburned clear-cut and the least when grown in soil from (i) a 20-year-old plantation that had been clear-cut and burned in the late 1950's and (ii) one old-growth forest. Tip formation was intermediate in soil from a second old-growth forest, a recently burned clear-cut, and a 40-year-old natural burn. Root weights followed the same trend, but top weights did not differ among the various soils. Ectomycorrhizal and total root tips of western hemlock (Tsugaheterophylla (Raf.) Sarg.) were lowest in soils from the plantation and recently burned clear-cut. Unlike Douglas-fir, western hemlock's tip production was not greater in the unburned clear-cut than in the old-growth forest soils. In this species, both top and root weights varied according to soil, with the largest seedlings produced in soil from the unburned clear-cut. With both species, there was a significant interaction between ectomycorrhizal type and soil type. Cenococcumgeophilum Fr. predominated on western hemlock and was reduced in soils from the burned clear-cut and plantation. In comparison with the mean for all soils, ectomycorrhizal types that predominated on Douglas-fir were enhanced in the unburned clear-cut soil and reduced in one old-growth soil, an effect apparently related to litter leachate.

Soil microbial biomass and microbial and mineralizable N in a clear-cut chronosequence on northern Vancouver Island, British Columbia

1995 ◽  
Vol 25 (10) ◽  
pp. 1595-1607 ◽  
Author(s):  
Scott X. Chang ◽  
Gordon F. Weetman ◽  
Caroline M. Preston
Keyword(s):  
Microbial Biomass ◽  
Vancouver Island ◽  
Old Growth ◽  
Clear Cutting ◽  
Old Growth Forest ◽  
Mineralizable N ◽  
Old Growth Forests ◽  
C And N ◽  
Microbial C ◽  
Microbial N

We studied the dynamics of microbial biomass and nitrogen in old-growth forests and in 3- and 10-year-old plantations established after clear-cutting and slash burning of old-growth western red cedar (Thujaplicata Donn ex D. Don)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) stands on northern Vancouver Island. Ten-year-old plantations, after initially growing well, were experiencing declining growth rates. Three forest floor layers: F (fermentation), woody F (Fw), and H (humus) were sampled four times in May, July, August, and October of 1992. Moisture content was significantly greater in the old-growth forests than in the plantations for F on July 16 (p < 0.05) and Fw (p < 0.10), but was not significantly different for H. Microbial biomass C and N were relatively constant throughout the sampling period, resulting in nonsignificant date effects. Microbial C content was in the order: old-growth forests > 10-year-old plantations > 3-year-old plantations. Microbial N content was significantly greater in the old-growth forest than in the young plantations for both F (p < 0.001) and H (p < 0.05) but was not different between the plantations. Therefore, the hypothesis that the microbial biomass acted as a net sink in the 10-year-old plantations by immobilizing N into the microbial N pool is rejected. Microbial C/N ratios were greater (p < 0.05) in the 10-year-old plantations than in the old-growth forests and in the 3-year-old plantations in H and on July 16 in F, indicating that microbial competition for N was probably a factor in the growth declining in the 10-year-old plantations. Extractable C and N and mineralizable N were generally higher in the old-growth forests than in the 3-year-old plantations and higher in the 3-year-old than in the 10-year-old plantations. As a result of better nutritional conditions, tree and understory foliage in the 3-year-old plantations had higher N concentrations and lower C/N ratios than in the 10-year-old plantations. Trees in the 10-year-old plantations displayed chlorotic symptoms and slow growth which were not observed in the 3-year-old plantations.

Crown dynamics and wood production of Douglas-fir trees in an old-growth forest

2017 ◽  
Vol 384 ◽  
pp. 157-168 ◽  
Author(s):  
H. Roaki Ishii ◽  
Stephen C. Sillett ◽  
Allyson L. Carroll
Keyword(s):  
Douglas Fir ◽  
Wood Production ◽  
Old Growth ◽  
Old Growth Forest
Sign in / Sign up

Export Citation Format

Share Document