Root biomass of regenerating aspen (Populus tremuloides) stands of different densities in Alberta

2001 ◽  
Vol 31 (6) ◽  
pp. 1012-1018 ◽  
Author(s):  
Annie DesRochers ◽  
Victor J Lieffers

In north-central Alberta, 12 plots (9 m2) were hydraulically excavated in young trembling aspen (Populus tremuloides Michx.) stands (5–10 years old) of different sucker density to quantify the effects of sucker density on the parental root system, on the formation of new roots and on the growth of suckers. All roots were collected and divided into live and dead parental roots and new root categories. Size and age of parent roots at the time of suckering were determined. Total biomass ranged from 1 to 18 t/ha of live roots. Living root biomass was proportional to stand density and leaf area index (LAI). Low-density stands had a higher proportion of dead roots. Suckers in plots with more parental root biomass/sucker had greater height growth. Root/shoot ratios ranged from 0.46 to 3.52 but were not correlated with stand densities. Stands with larger basal area of suckers and greater mean parent root diameter produced more biomass of new roots. This research suggests that young sucker-origin aspen stands support a large underground biomass and that high sucker densities and LAI are required to prevent loss of parental root biomass.

1984 ◽  
Vol 14 (2) ◽  
pp. 259-265 ◽  
Author(s):  
John A. Pearson ◽  
Timothy J. Fahey ◽  
Dennis H. Knight

Bole, branch, foliage, root crown, and lateral root biomass of Pinuscontorta ssp. latifolia (Engelm. ex Wats.) Critchfield forests in southeastern Wyoming were estimated by a combination of aboveground dimension analysis, belowground planar intersect sampling, and soil coring. Total biomass of six stands ≥75 years old ranged from 123 to 180 Mg/ha, and roof:shoot ratios were much higher in two very dense stands than in four more open stands. Average proportions of biomass in boles, branches, foliage, woody roots, and fine roots were 61, 7, 6, 20, and 6%, respectively. Leaf area index ranged from 4.5 to 9.9. Leaf area per unit sapwood area ranged from 0.20 to 0.57 m2/cm2in stands of different densities, ages, and sites. Sapwood area was a more precise predictor of foliage biomass than was basal area for the low to moderate density stands, but was marginally inferior to basal area for two high density stands (>9000 trees/ha).


1994 ◽  
Vol 72 (1) ◽  
pp. 39-51 ◽  
Author(s):  
David W. Huffman ◽  
John C. Tappeiner II ◽  
John C. Zasada

Regeneration of salal (Gaultheria shallon Pursh.) by seedling establishment and vegetative expansion was examined under various forest conditions in the central Coast Range of Oregon. Size and expansion rate of individual clonal fragments were negatively correlated with overstory stand density (p ≤ 0.039). As overstory basal area increased from 25 to 75 m2/ha, mean annual growth percentage of clone rhizome systems decreased from 23.7 to 0.0% and mean total rhizome length decreased from 102 to 0.89 m. Interclonal competition in dense clumps of salal apparently causes rhizomes to die and clones to fragment. In these patches, rhizome biomass and density, aerial stem biomass and density, and total biomass were negatively correlated with overstory density (p ≤ 0.01). For example, in clearcuts, salal clumps had up to 177.7 m rhizome/m2 and 346 stems/m2, whereas patches under dense overstories had as few as 10.6 m rhizome/m2 and 19 stems/m2. Aerial stem populations had uneven-age distributions of aerial stems in all overstory conditions. This structure is apparently maintained through annual production of new ramets. Salal seedling establishment rates were significantly affected by study site location, overstory density, and substrate (p ≤ 0.05). Two-year survival was highest on rotten logs and stumps in thinned stands. Key words: clonal morphology, clone populations, Douglas-fir forests, Gaultheria shallon, seedling establishment, vegetative expansion.


2001 ◽  
Vol 31 (12) ◽  
pp. 2089-2097 ◽  
Author(s):  
Thomas T Veblen ◽  
Dominik Kulakowski ◽  
Karen S Eisenhart ◽  
William L Baker

As windstorm intensity increases above some threshold, disturbance spread and damage patterns are expected to be less strongly shaped by preblowdown forest composition and structure than by the pattern of the storm itself. We examined this generalization by analyzing differences in wind damage among tree species and stands following a severe blowdown in 1997 affecting over 10 000 ha of subalpine forest in the Routt Divide area of northern Colorado, U.S.A. Individual tree traits such as species, height, and status as standing dead or alive strongly influenced the amount and type (uprooting vs. snapping) of wind damage. Populus tremuloides Michx. exhibited much less uprooting and overall damage than the conifers. Among the canopy trees of the conifer species, Pinus contorta Dougl. ex. Loud and Abies lasiocarpa (Hook.) Nutt. sustained the lowest and highest rates of snapping, respectively. Standing dead conifers were more likely to be snapped than uprooted, and taller trees were more likely to be damaged than shorter trees. Stand-level characteristics such as stand density, amount of dead basal area, and species composition were predictive of the amount of wind damage for areas of moderate- but not high-severity blowdown. Even in such an extreme windstorm as the Routt blowdown, which had estimated wind speeds of 200–250 km/h, individual tree attributes and stand-level characteristics significantly influenced the severity and type of wind damage.


2003 ◽  
Vol 18 (4) ◽  
pp. 259-266 ◽  
Author(s):  
Joel D. McMillin ◽  
Kurt K. Allen ◽  
Daniel F. Long ◽  
Jeri Lyn Harris ◽  
José F. Negrón

Abstract Western balsam bark beetle, Dryocoetes confusus (Coleoptera: Scolytidae), has caused widespread mortality of subalpine fir (Abies lasiocarpa) in western North America throughout the past decade. The objectives of this study were to document the effects of this mortality, relate mortality to pre-existing stand conditions, and investigate the role of storm-damaged fir in beetle population dynamics in north-central Wyoming. Transect cruise lines and pairs of infested and uninfested plots were installed to detect changes in the forest overstory and understory and to determine associations between stand conditions and beetle-caused fir mortality. On average, beetles killed more than 70 trees/ac over the last several years. This mortality resulted in significant decreases in: subalpine fir basal area, trees per acre, stand density index, and the percentage of subalpine fir stems in the overstory. Small, but significant increases were detected in the understory; herbaceous plant abundance increased in the infested plots compared with the noninfested plots. Moreover, significant positive linear relationships were found between the amount of fir mortality and the percentage of subalpine fir trees in a stand, subalpine fir basal area, and subalpine fir stand density index. In addition, a significant positive linear relationship was found between the percentage of wind-caused downed fir logs in an area and the percentage of logs utilized by western balsam bark beetle. The blowdown events that occurred in the mid-1990s in combination with a high percentage of fir component has provided ideal conditions for continued beetle expansion. West. J. Appl. For. 18(4):259–266.


Author(s):  
Rathod Digvijaysinh ◽  
Yogesh Kumar ◽  
Gaurav Chand Ramola ◽  
Dhaval Prajapati ◽  
C. S. Dhanai ◽  
...  

Deodar is typically gregarious and is usually found in pure stands. It is one of the most important timber species in the forests of North Indian Himalayas. The objective of the present study was the assessment of variation in volume and biomass along with the carbon holding capacity of different deodar forests. The present study was undertaken in ten different forests sites, assessed by laying out three 0.1 ha sample plots randomly on each location. Total enumeration of trees within the sample plot was done by measuring girth and height of all the trees. Further, data collected from stand were computed for dbh, basal area, volume, stand density and canopy cover. The above ground biomass densities (AGBD), below ground biomass density (BGBD), total biomass density (TBD), total carbon density (TCD) were examined for variation of biomass and carbon stock. The results derived from field data during the study revealed that the values range from 42.10 to 57.07 cm (diameter at breast height), 1.37 to 2.84 m2 trees-1 (basal area), 19.68 to 37.64 m (height), 1.44 m3 tree-1 to 4.27 m3 tree-1 (volume), 227 to 407 individual ha-1 (stand density) and 57.91% to 80.60% (canopy cover) respectively. The values of AGBD (428.57 to 1279.51 Mg ha-1), BGBD (97.41 to 256.14 Mg ha-1), TBD (525.98 to 1535.65 Mg ha-1), and TCD (767.83 to 262.99 Mg ha-1) were recorded in different study sites and highest values was observed in Kanasar-I site. On the basis of above results it can be concluded that the healthy stand growth means presence of trees in all diameter classes. The Kanasar-I has more prominent capacity to storage biomass and carbon stock. Deodar being a slow growing conifer will provide a long term and high carbon storage than broadleaf species forest. Therefore, protecting deodar forest would have the largest impact, per unit area, on reducing carbon emission from deforestation.


2007 ◽  
Vol 37 (2) ◽  
pp. 343-355 ◽  
Author(s):  
Nate G. McDowell ◽  
Henry D. Adams ◽  
John D. Bailey ◽  
Thomas E. Kolb

We examined the response of growth efficiency (GE), leaf area index (LAI), and resin flow (RF) to stand density manipulations in ponderosa pine ( Pinus ponderosa Dougl. ex Laws.) forests of northern Arizona, USA. The study used a 40 year stand density experiment including seven replicated basal area (BA) treatments ranging from 7 to 45 m2·ha–1. Results were extended to the larger region using published and unpublished datasets on ponderosa pine RF. GE was quantified using basal area increment (BAI), stemwood production (NPPs), or volume increment (VI) per leaf area (Al) or sapwood area (As). GE per Al was positively correlated with BA, regardless of numerator (BAI/Al, NPPs/Al, and VI/Al; r2 = 0.84, 0.95, and 0.96, respectively). GE per As exhibited variable responses to BA. Understory LAI increased with decreasing BA; however, total (understory plus overstory) LAI was not correlated with BA, GE, or RF. Opposite of the original research on this subject, resin flow was negatively related to GE per Al because Al/As ratios decline with increasing BA. BAI, and to a lesser degree BA, predicted RF better than growth efficiency, suggesting that the simplest measurement with the fewest assumptions (BAI) is also the best approach for predicting RF.


2009 ◽  
Vol 24 (1) ◽  
pp. 24-32 ◽  
Author(s):  
John-Pascal Berrill ◽  
Kevin L. O'Hara

Abstract Multiaged management regimes and harvesting scenarios were simulated in coast redwood (Sequoia sempervirens [D. Don.] Endl.) stands using models of stand growth and yield (CRYPTOS) and stocking assessment (redwood MASAM). Various stocking and age-class combinations were modeled on site index 100 and 130 ft (50 years). Results demonstrated how the number of cohorts, upper limit of stocking, and cohort densities affected growth and yield. Board foot volume increment reached a plateau in stands with a prescribed upper limit of stocking above leaf area index 7.2 to 8.6. Productivity did not differ between stands with two to five cohorts producing the same tree size at harvest. It was affected by stand structure when a cutting cycle of 20 years was prescribed in stands with three to five cohorts. Stands with the same density returned to the upper limit of stocking much sooner on better sites. Prolonging the cutting cycle by reducing stand density resulted in larger tree sizes at harvest and greater productivity. The growth of trees remaining after cutting 10–50% of stand basal area and growth of new stump sprouts were also simulated. Stands quickly returned to preharvest stocking after light cutting, implying that heavy or frequent light cutting is needed to sustain growth and vigor of regeneration in multiaged coast redwood stands.


1987 ◽  
Vol 2 (4) ◽  
pp. 124-128 ◽  
Author(s):  
Thomas F. Hughes ◽  
Christopher R. Latt ◽  
John C. Tappeiner ◽  
Michael Newton

Abstract To help foresters assess site occupancy of seed-established stands of varnishleaf (Ceanothus velutinus var. laevigatus) deerbrush (Ceanothus integerrimus), and whiteleaf manzanita (Arctostaphylos viscida), we developed equations for estimating their aboveground biomass and leaf area. From 9 to 14 pure stands from 2 to 20 years old were selected for each species in southwest Oregon and northern California. Individual stems of Ceanothus species and whole bushes of manzanita were destructively sampled Regression equations for leaf and total biomass of manzanita plants and for stems of Ceanothus sp. showed that these variables were highly correlated with trunk or stem diameter (r² = 0.85 - 0.99). Total biomass, leaf biomass, and leaf area index (LAI) of stands can be estimated accurately from measurements of stem or trunk basal area (r² = 0.87 - 0.99). Stand age (yr) and average stem length (cm) are also reliable estimators (r² = 0.74 - 0.82). It appears that stands of varnishleaf attain a maximum LAI of 5.5 m²/m² by 7 years, whereas the maximum values for deer-brush and manzanita were 2.8 and 3.5, respectively, at about 15 years. Stands of all three species apparently continue to produce net biomass well beyond 16 years of age. West. J. Appl. For. 2(4):124-128, October 1987.


2005 ◽  
Vol 9 (6) ◽  
pp. 1-22 ◽  
Author(s):  
Ted R. Feldpausch ◽  
Susan J. Riha ◽  
Erick C. M. Fernandes ◽  
Elisa V. Wandelli

Abstract The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; however, the return of forest and canopy structure following abandonment is not well understood. This study examined the development of leaf area index (LAI), canopy cover, aboveground biomass, stem density, diameter at breast height (DBH), and basal area (BA) by growth form and diameter class for 10 SFs regenerating from abandoned pastures. Biomass accrual was tree dominated, constituting ≥94% of the total measured biomass in all forests abandoned ≥4 to 6 yr. Vine biomass increased with forest age, but its relative contribution to total biomass decreased with time. The forests were dominated by the tree Vismia spp. (>50%). Tree stem density peaked after 6 to 8 yr (10 320 stems per hectare) before declining by 42% in the 12- to 14-yr-old SFs. Small-diameter tree stems in the 1–5-cm size class composed >58% of the total stems for all forests. After 12 to 14 yr, there was no significant leaf area below 150-cm height. Leaf area return (LAI = 3.2 after 12 to 14 yr) relative to biomass was slower than literature-reported recovery following slash-and-burn, where LAI can reach primary forest levels (LAI = 4–6) in 5 yr. After 12 to 14 yr, the colonizing vegetation returned some components of forest structure to values reported for primary forest. Basal area and LAI were 50%–60%, canopy cover and stem density were nearly 100%, and the rapid tree-dominated biomass accrual was 25%–50% of values reported for primary forest. Biomass accumulation may reach an asymptote earlier than expected because of even-aged, monospecific, untiered stand structure. The very slow leaf area accumulation relative to biomass and to reported values for recovery following slash-and-burn indicates a different canopy development pathway that warrants further investigation of causes (e.g., nutrient limitations, competition) and effects on processes such as evapotranspiration and soil water uptake, which would influence long-term recovery rates and have regional implications.


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