Stream channel configuration, landform, and riparian forest structure in the Cascade Mountains, Washington

2000 ◽  
Vol 57 (4) ◽  
pp. 699-707 ◽  
Author(s):  
Byron W Rot ◽  
Robert J Naiman ◽  
Robert E Bilby

The hierarchical relationship of five key elements, valley constraint, riparian landform, riparian plant community, channel type, and channel configuration, are described for 21 sites in mature to old-growth riparian forests of the western Cascades Mountains, Washington, U.S.A. Channel type (bedrock, plane-bed, and forced pool-riffle) was closely related to channel configuration (especially large woody debris (LWD) volume, density, and LWD-formed pools) at the smallest spatial scale and valley constraint at the largest. Valley constraint significantly influenced off-channel habitat (r2 = 0.71) and LWD volume within forced pool-riffle channels (r2 = 0.58). Riparian plant community composition was differentiated by four landform classes: three alluvial landforms based on height above the channel and one based on hillslope. Just above the active channel, floodplain landforms contained more deciduous stems than conifer and greater conifer basal area than deciduous. Conifers dominated other landforms. The diameter of in-channel LWD increased with the age of the riparian forest (r2 = 0.34). In old-growth forests, LWD diameter was equivalent to or greater than the average riparian tree diameter for all sites. In younger forests, the mixed relationship between LWD and riparian tree diameter may reflect a combination of LWD input from the previous old-growth stand and LWD input from the existing stand.

2001 ◽  
Vol 31 (12) ◽  
pp. 2067-2079 ◽  
Author(s):  
Robert L Deal

The effects of partial cutting on plant species richness, community structure, and several understory species that are important for deer forage were evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12–96 years ago when 16–96% of the former stand basal area was removed. The species richness and community structure of understory plants were similar in uncut and partially cut plots. However, plots where more than 50% of the basal area was cut had a significantly different plant community structure. Species composition and abundance also appeared to be distinctly different between hemlock-dominated and spruce-dominated stands. Partial cutting did not significantly change abundance for most of the important forage species for deer. The similarity in plant community structure between partially cut and uncut old-growth stands may be related to forest stand structures. The heterogeneous stand structures that develop after partial cutting are more similar to old-growth stands than to the uniform young-growth stands that develop after stand replacing disturbances such as clear-cutting.


2002 ◽  
Vol 32 (4) ◽  
pp. 742-750 ◽  
Author(s):  
Robert L Edmonds ◽  
Georgia LD Murray

Overstory litterfall rates and nutrient returns were determined in an old-growth temperate rainforest watershed in the Hoh River valley, Olympic National Park, Washington. Litter was sorted into green needles, senescent needles, fine wood, reproductive, and miscellaneous litter (mostly arboreal lichens and mosses). Understory and coarse woody debris inputs were not determined. Total annual overstory litterfall averaged 3594 kg·ha–1 and varied among the six plant communities in the watershed. There was a trend for litterfall to be higher in the upper watershed; elevations ranged from 180 to 850 m. Needles provided the greatest amount of litterfall (60%) with woody litter and other material averaging 18 and 22%, respectively. Highest senescent needle litterfall occurred from July to October, but highest woody litterfall was from January to April. Green needles provided only 3% of annual needle litterfall. Green and senescent needle litterfall were related to western hemlock (Tsuga heterophylla (Raf.) Sarg.) basal area, suggesting that this shade-tolerant species was the greatest contributor to needle litterfall. The following quantities (kg·ha–1) of nutrients were returned to the forest floor annually: Ca, 26.8; N, 24.6; K, 4.0; Mg, 3.0; P, 2.9; Mn, 1.7; and Na, 1.2.


1996 ◽  
Vol 26 (7) ◽  
pp. 1218-1227 ◽  
Author(s):  
Craig W. Hedman ◽  
David H. Van Lear ◽  
Wayne T. Swank

Large woody debris (LWD) is an important ecological component of mountain streams. However, the relation of LWD loading and riparian forest composition is poorly understood in the southern Appalachians. In this study, 500-m reaches of 11 riparian forest–stream systems representing a 300-year sere were inventoried and measured to obtain quantitative estimates and descriptions of in-stream LWD. Loading volumes ranged from 7.1 to 31.2 m3/100 m of stream, or between 3.6 and 13.2 kg/m2. LWD loadings were highly variable during midseral stages of plant community succession, primarily because of the wide range in loading of American chestnut (Castaneadentata (Marsh.) Borkh.). Loadings increased linearly in late-successional through old-growth systems over a 165-year interval. Eastern hemlock (Tsugacanadensis (L.) Carrière) and American chestnut were the most dominant carry-over LWD species in midsuccessional stream systems. Loading of eastern hemlock LWD increased from midsuccessional through old-growth stages as the species became dominant in the riparian forest. Without carry-over debris, LWD loadings would be extremely low in midsuccessional stream systems. American chestnut was a major component of LWD in midsuccessional stream systems, despite the fact that it has been unavailable for recruitment for decades.


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.


2014 ◽  
Vol 11 (7) ◽  
pp. 11597-11634
Author(s):  
S. Bernal ◽  
A. Lupon ◽  
M. Ribot ◽  
F. Sabater ◽  
E. Martí

Abstract. Headwater streams have a strong capacity to transform and retain nutrients, and thus, a longitudinal decrease in stream nutrient concentrations would be expected from in-stream nutrient removal alone. Yet, a number of other factors within the catchment, including biogeochemical processing within the riparian zone and export to streams, can contribute to stream nutrient concentration, which may overcome the effect of in-stream biogeochemical processing. To explore this idea, we analyzed the longitudinal patterns of stream and riparian groundwater concentrations for chloride (Cl−), nitrate (NO3−), ammonium (NH4+), and phosphate (PO43−) along a 3.7 km reach at an annual scale. The reach showed a gradual increase in stream and riparian width, riparian tree basal area, and abundance of riparian N2-fixing tree species. Concentrations of Cl− indicated a~strong hydrological connection at the riparian-stream edge. However, stream and riparian groundwater nutrient concentrations showed a moderate to null correlation, suggesting high biogeochemical processing at the riparian-stream edge and within the stream. A mass balance approach along the reach indicated that, on average, in-stream net nutrient uptake prevailed over release for NH4+ and PO43−, but not for NO3−. On an annual basis, in-stream processes contributed to change stream input fluxes by 11%, 26%, and 29% for NO3−, NH4+, and PO43−, respectively. Yet, longitudinal trends in concentration were not consistent with the prevailing in-stream biogeochem ical processes. During the riparian dormant period, stream concentration decreased along the reach for NO3−, but increased for NH4+ and PO43−. During the riparian vegetative period, NO3− and PO43− increased along the reach while NH4+ showed no clear pattern. These longitudinal trends were partially related to riparian forest features and groundwater inputs, especially for NO3− and PO43−. Our study suggests that even though in-stream biogeochemical processing was substantial, the riparian zone can modulate the longitudinal variation in stream nutrient chemistry in this headwater stream.


2003 ◽  
Vol 79 (3) ◽  
pp. 632-644 ◽  
Author(s):  
Bruce J Stewart ◽  
Peter D Neily ◽  
Eugene J Quigley ◽  
Lawrence K Benjamin

A study of four old-growth stands in Nova Scotia was conducted to document the ecological characteristics of these currently rare Acadian forest ecosystems. Stands were selected to represent the two dominant climax forest types, hemlock–red spruce–eastern white pine, and sugar maple–yellow birch–beech. Data include measurements of age structure, species composition, diameter distribution, basal area, height, coarse woody debris, snags, vertical structure, and canopy condition. All stands were determined to be uneven-aged. Old-growth reference ages calculated for the stands ranged from 164 to 214 years. All stands displayed broad diameter distributions that had peak basal area representation in the 40- to 50-cm diameter classes. Volumes of dead wood ranged from 111 to 148 m3/ha in the softwood stands and from 63 to 83m3/ha in the hardwood stands. Dead wood consisted of approximately one-third snags and two thirds downed coarse woody debris. Measurements from the stands were used to evaluate Nova Scotia's recently developed Old Forest Scoring System. Six stand attributes were rated for a maximum score of 100: stand age, primal value, number of large-diameter trees, length of large-diameter dead wood, canopy structure, and understorey structure. Based on the age attribute, three of the four stands were classed as Mature Old Growth and one was very close, indicating that all are in the shifting mosaic stage of late forest succession. The scores for all stands were relatively high, ranging from 75 to 85, as would be expected from some of the best old-growth stands in the province. Key words: old growth, climax, primal, late succession, uneven-aged, scoring, coarse woody debris, age structure, diameter, Acadian forest, northern hardwood, red spruce, eastern hemlock, white pine, sugar maple, yellow birch, American beech


2017 ◽  
Vol 26 (2) ◽  
pp. 148 ◽  
Author(s):  
Grant Wardell-Johnson ◽  
Liam Crellin ◽  
Casey Napier ◽  
Garrett Meigs ◽  
Alyssa Stevenson ◽  
...  

Tall eucalypt old-growth forests are notable for their large, old (i.e. venerable) trees and have both significant conservation value and high carbon stores. We investigated whether canopy height and biomass had recovered in an old-growth red tingle (Eucalyptus jacksonii) forest 78 years after a high-intensity fire. We recorded species, diameter, hollow butting and height of all 596 trees >10-cm diameter at breast height, as well as fine and coarse woody debris, in a 3.55-ha plot near Nornalup, south-western Australia. Pre-fire canopy height was estimated by allometrics derived from tree height and diameter, and diameter and length of recently fallen branches. Of the basal area (75.0 m2 ha–1), 92.7% was eucalypt (chiefly E. jacksonii), with regeneration accounting for only 8.5% of the total. Although canopy species composition apparently did not change following fire, stand height and biomass had not recovered to pre-1937 levels by 2015. Canopy height remained 5.06 m (11%) less and biomass 25% less, 78 years after the fire. The combination of intense fire and a warmer, drier climate appears to have prevented recovery of forest height and structure at this site. These findings indicate that ecologically important, venerable trees are increasingly vulnerable to canopy fire and climate change.


1994 ◽  
Vol 24 (8) ◽  
pp. 1672-1683 ◽  
Author(s):  
Lucy E. Tyrrell ◽  
Thomas R. Crow

We studied the dynamics of coarse woody debris (logs and snags) in old-growth forests by estimating rates of tree mortality, snag change, and log decay in hemlock–hardwood stands located in northern Wisconsin and northern Michigan. To estimate mortality and snag changes, we recensused live trees and dead snags in permanent plots in 15 stands. We also recorded recent mortality along transects, and noted category of mortality (standing death, breakage, or uprooting) for gap-maker trees and logs in 25 stands. Decay rates were estimated from a simple exponential model of wood density from log sections against the age of the wood since tree death, and from ages of trees growing on decaying "nurse" logs. From data obtained in permanent plots, annual tree mortality averaged 0.9% original basal area, 0.9% original live tree density, and 4.8 trees/ha. Of the three categories of tree mortality, standing death accounted for 62% of all mortality, while breakage represented 25%, and uprooting, 13%. Based on origin of logs, species composition affected category of mortality. Eastern hemlock (Tsugacanadensis (L.) Carr.) was significantly more prone to uprooting while yellow birch (Betulaalleghaniensis Britton) and paper birch (Betulapapyrifera Marsh.) were less prone to uprooting than expected if independence of species and categories of mortality were assumed (χ2 = 216.5, df = 14, p < 0.001). Changes in snags (fragmentation to shorter snags or collapse at the base) occurred for <7% of the original snags annually. Fragmentation occurred for 2.1 snags/(ha × year), and collapse for 1.3 snags/(ha × year). We estimated that it takes nearly 200 years for hemlock logs to lose structural integrity and become partially incorporated into the soil. At >350 years, the two oldest hemlock–hardwood stands had accumulated volumes of logs >65 m3/ha distributed among all decay classes, and appeared to be at a dead wood equilibrium in which rates of log production from mortality balance rates of wood loss by decay.


2020 ◽  
Vol 49 (2) ◽  
pp. 391-404 ◽  
Author(s):  
Patrick J Engelken ◽  
Deborah G McCullough

Abstract Extensive ash (Fraxinus spp.) mortality has been reported across much of the area in eastern North America invaded by emerald ash borer (Agrilus planipennis Fairmaire), but indirect effects of emerald ash borer invasion on native forest insects are not well-studied. We assessed cerambycid beetle (Coleoptera: Cerambycidae) species captured in baited cross-vane panel traps during the 2017 and 2018 growing seasons. Traps were placed in 12 riparian forest sites distributed across three watersheds selected to represent the temporal gradient of the emerald ash borer invasion from southeastern to southwestern Michigan. Although ash species originally dominated overstory vegetation in all sites, &gt;85% of ash basal area has been killed by emerald ash borer. We captured a total of 3,645 beetles representing 65 species and five subfamilies. Species assemblages in southeast sites, with the longest history of emerald ash borer invasion, differed from those in south central and southwest Michigan, which were similar. These differences were largely due to three species, which accounted for &gt;60% of beetle captures in southeast Michigan. Associations among site-related variables and beetle captures indicated cerambycid species assemblages were associated most strongly with abundance and decay stage of coarse woody debris. During both years, &gt;90% of cerambycid species were captured by mid-summer but seasonal activity differed among and within tribes. Numbers of beetles captured by canopy and ground traps were similar but species richness was higher in canopy traps than ground traps. Results suggest inputs of emerald ash borer-killed ash can have temporally lagged, secondary effects on cerambycid communities.


1991 ◽  
Vol 21 (11) ◽  
pp. 1567-1572 ◽  
Author(s):  
Robert N. Muller ◽  
Yan Liu

Volume and mass of coarse woody debris (> 20 cm diameter) in an old-growth forest on the Cumberland Plateau in southeastern Kentucky averaged 66.3 m3/ha and 21.8 Mg/ha, respectively. Coarse woody debris was patchily distributed among 80 sample plots (0.04 ha each), with 10 plots containing 39% of the total mass. Coarse woody debris mass was inversely, although not strongly, related to plot basal area. While 23 species contributed to the accumulation of coarse woody debris, five accounted for 72% of the total mass. These included Quercusprinus L. (25% of the total), Fagusgrandifolia L. (16%), Quercusalba L. (12%), Castaneadentata (Marsh.) Borkh. (11%), and Quercusvelutina Lam. (9%). The few studies of coarse woody debris in old-growth deciduous forests of North America suggest a regional pattern of accumulation correlated with temperature. In warmer regions, old-growth deciduous forests accumulate a mass in the range of 22–32 Mg/ha, while in cooler ecosystems, coarse woody debris ranges from 34 to 49 Mg/ha.


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