Effect of understory competition on distribution and recovery of 15N applied to a western red cedar–western hemlock clear-cut site

1996 ◽  
Vol 26 (2) ◽  
pp. 313-321 ◽  
Author(s):  
Scott X. Chang ◽  
Gordon F. Weetman ◽  
Caroline M. Preston ◽  
Kevin McCullough ◽  
John Barker
Keyword(s):  
Dilution Effect ◽  
Western Hemlock ◽  
Total Recovery ◽  
Total N ◽  
Clear Cut ◽  
Red Cedar ◽  
Growing Seasons ◽  
N Enrichment ◽  
Western Red Cedar ◽  
Respective Species

Fertilizer labeled with 15N was used to study the fate of N in forest soil–plant systems with (control) and without competition (treated) from an ericaceous evergreen shrub, salal (Gaultheriashallon Pursh), on a western red cedar (Thujaplicata Donn ex D. Don)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) clear-cut site on northern Vancouver Island. Fertilizer was applied in April 1991 at 200 kg N•ha−1 as (NH4)2SO4 (3.38044% 15N enrichment) to single-tree plots of 1 m radius. Four-year-old western red cedar, western hemlock, and Sitka spruce (Piceasitchensis (Bong.) Carrière) were used and the plots were destructively sampled after two growing seasons (October 1992). The distribution of 15N within trees was virtually unaffected by the treatment but displayed differences among species. The majority of the 15N in a tree was found in the current-year needles. Because of the dilution effect, 15N abundances in the above ground tree components were not different between treatments but 15N contents were significantly increased by salal removal. The pattern of and treatment effect on total N distribution were similar to those of 15N. Total recovery by trees of applied 15N was 7.7, 17.8, and 10.3% in the treated plots planted with cedar, hemlock, and spruce, respectively. The corresponding values for the control plots were 4.1, 2.0, and 4.9%. Understory in the control plots immobilized 14.8, 24.6, and 13.5% of the applied N for plots planted with the respective species. Total recoveries in soil and vegetation ranged from 57 to 87%, of which 59 to 82% was recovered in the soil compartments. Results clearly showed that trees competed poorly with the understory vegetation for the applied fertilizer N.

Patterns of log decay in old-growth Douglas-fir forests

1987 ◽  
Vol 17 (12) ◽  
pp. 1585-1595 ◽  
Author(s):  
Phillip Sollins ◽  
Steven P. Cline ◽  
Thomas Verhoeven ◽  
Donald Sachs ◽  
Gody Spycher
Keyword(s):  
C:N Ratio ◽  
Dry Weight ◽  
Douglas Fir ◽  
Time Span ◽  
Western Hemlock ◽  
Tissue Type ◽  
Old Growth ◽  
Total N ◽  
Red Cedar ◽  
Western Red Cedar

Fallen boles (logs) of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and western red cedar (Thujaplicata Donn) in old-growth stands of the Cascade Range of western Oregon and Washington were compared with regard to their physical structure, chemistry, and levels of microbial activity. Western hemlock and western red cedar logs disappeared faster than Douglas-fir logs, although decay rate constants based on density change alone were 0.010/year for Douglas-fir, 0.016/year for western hemlock, and 0.009/year for western red cedar. We were unable to locate hemlock or red cedar logs older than 100 years on the ground, but found Douglas-fir logs that had persisted up to nearly 200 years. Wood density decreased to about 0.15 g/cm3 after 60–80 years on the ground, depending on species, then remained nearly constant. Moisture content of logs increased during the first 80 years on the ground, then remained roughly constant at about 250% (dry-weight basis) in summer and at 350% in winter. After logs had lain on the ground for about 80 years, amounts of N, P, and Mg per unit volume exceeded the amount present initially. Amounts of Ca, K, and Na remained fairly constant throughout the 200-year time span that was studied (100-year time span for Na). N:P ratios converged toward 20, irrespective of tree species or wood tissue type. C:N ratios dropped to about 100 in the most decayed logs; net N was mineralized during anaerobic incubation of most samples with a C:N ratio below 250. The ratio of mineralized N to total N increased with advancing decay. Asymbiotic bacteria in fallen logs fixed about 1 kg N ha−1 year−1, a substantial amount relative to system N input from precipitation and dry deposition (2–3 kg ha−1 year−1).

Growth of western red cedar seedlings in relation to microtopography, forest floor nutrient status, and fireweed and salal on clear-cut sites in coastal British Columbia

1992 ◽  
Vol 22 (3) ◽  
pp. 273-278 ◽  
Author(s):  
Christian Messier ◽  
James P. Kimmins
Keyword(s):  
British Columbia ◽  
Forest Floor ◽  
Nutrient Status ◽  
Ecological Significance ◽  
Total N ◽  
Cellulose Decomposition ◽  
Clear Cut ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Coastal British Columbia

The growth of western red cedar (Thujaplicata Donn) seedlings was studied in relation to microtopography, to forest floor nutrient status, and to fireweed (Epilobiumangustifolium L.) and salal (Gaultheriashallon Pursh) abundance on 4-year-old logged and burned sites dominated by salal on northern Vancouver Island, British Columbia. These relationships were sought to determine some possible factors at the microsite level that influence the growth of western red cedar on recently clear-cut sites. Western red cedar growth and fireweed abundance and height were significantly greater in depressions than on flats and mounds, but these differences were not related to any major differences in forest floor pH, cellulose decomposition, total N and P, and available NH4+, NO3−, and phosphate P as measured using resin bags. The ecological significance of and possible reasons for the lack of correlation found between (i) western red cedar and fireweed growth and (ii) many measures of forest floor nutrient status are discussed.

Mass and nutrient content of woody debris and forest floor in western red cedar and western hemlock forests on northern Vancouver Island

1993 ◽  
Vol 23 (6) ◽  
pp. 1052-1059 ◽  
Author(s):  
Rodney J. Keenan ◽  
Cindy E. Prescott ◽  
J.P. Hamish Kimmins
Keyword(s):  
Forest Floor ◽  
Forest Type ◽  
Woody Debris ◽  
Nutrient Content ◽  
Vancouver Island ◽  
Western Hemlock ◽  
N Availability ◽  
Red Cedar ◽  
The Mean ◽  
Western Red Cedar

Biomass and C, N, P, and K contents of woody debris and the forest floor were surveyed in adjacent stands of old-growth western red cedar (Thujaplicata Donn)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) (CH type), and 85-year-old, windstorm-derived, second-growth western hemlock–amabilis fir (Abiesamabilis (Dougl.) Forbes) (HA type) at three sites on northern Vancouver Island. Carbon concentrations were relatively constant across all detrital categories (mean = 556.8 mg/g); concentrations of N and P generally increased, and K generally decreased, with increasing degree of decomposition. The mean mass of woody debris was 363 Mg/ha in the CH and 226 Mg/ha in the HA type. The mean forest floor mass was 280 Mg/ha in the CH and 211 Mg/ha in the HA stands. Approximately 60% of the forest floor mass in each forest type was decaying wood. Dead woody material above and within the forest floor represented a significant store of biomass and nutrients in both forest types, containing 82% of the aboveground detrital biomass, 51–59% of the N, and 58–61% of the detrital P. Forest floors in the CH and HA types contained similar total quantities of N, suggesting that the lower N availability in CH forests is not caused by greater immobilization in detritus. The large accumulation of forest floor and woody debris in this region is attributed to slow decomposition in the cool, wet climate, high rates of detrital input following windstorms, and the large size and decay resistance of western red cedar boles.

Mass Transfer Characteristics of Western Hemlock and Western Red Cedar

Holzforschung ◽  
2002 ◽  
Vol 56 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Anastasios Koumoutsakos ◽  
Stavros Avramidis
Keyword(s):  
Mass Transfer ◽  
Western Hemlock ◽  
Transfer Characteristics ◽  
Red Cedar ◽  
Western Red Cedar

Availability of N and P in the forest floors of adjacent stands of western red cedar–western hemlock and western hemlock–amabilis fir on northern Vancouver Island

1993 ◽  
Vol 23 (4) ◽  
pp. 605-610 ◽  
Author(s):  
C. E. Prescott ◽  
M.A. McDonald ◽  
G.F. Weetman
Keyword(s):  
Forest Floor ◽  
Forest Type ◽  
Western Hemlock ◽  
Red Cedar ◽  
Floor Layer ◽  
Second Growth ◽  
Extractable P ◽  
Western Red Cedar ◽  
Forest Floors ◽  
Floor Material

Availability of N and P was compared in the forest floors of old-growth forests of western red cedar (Thujaplicata Donn)and western hemlock (Tsugaheterophylla (Raf.) Sarg.) (CH forests), and second-growth forests of western hemlock and amabilis fir (Abiesamabilis (Dougl.) Forbes) (HA forests) of windthrow origin. Five samples of each forest floor layer (litter, fermentation (woody and nonwoody), and humus (woody and nonwoody)) were collected from three forests of each type (CH and HA). All layers of CH forest floors had smaller concentrations of total and extractable N and mineralized less N during 40-day aerobic incubations in the laboratory. Total and extractable P was lower in the litter layer of CH forest floors. Seedlings of western red cedar, Sitka spruce (Piceasitchensis (Bong.) Carr.), western hemlock, and amabilis fir grown from seed in forest floor material from CH forests grew more slowly and took up less N and P than did seedlings grown in HA forest floor material. The low supply of N and P in CH forest floors may contribute to the nutrient supply problems encountered by regenerating trees on cutovers of this forest type.

Responses of western hemlock, Pacific silver fir, and western red cedar plantations on northern Vancouver Island to applications of sewage sludge and inorganic fertilizer

1993 ◽  
Vol 23 (9) ◽  
pp. 1815-1820 ◽  
Author(s):  
G.F. Weetman ◽  
M.A. McDonald ◽  
C.E. Prescott ◽  
J.P. Kimmins
Keyword(s):  
Sewage Sludge ◽  
Vancouver Island ◽  
Western Hemlock ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Phosphorus Fertilization ◽  
Silver Fir ◽  
Nitrogen And Phosphorus ◽  
Red Cedar ◽  
Western Red Cedar

A field experiment was designed to determine whether or not municipal sewage sludge would be effective for fertilization for chlorotic and checked plantations of western hemlock (Tsugaheterophylla (Raf.) Sarg.), Pacific silver fir (Abiesamabilis (Dougl.) Forbes), and western red cedar (Thujaplicata Donn ex. D. Don) already shown to be responsive to conventional nitrogen and phosphorus fertilization. Sewage sludge was applied at an estimated rate of 500 kg N/ha and 133 kg P/ha and ammonium nitrate and triple superphosphate were applied at 225 kg N/ha and 75 kg P/ha to plots planted 8 years earlier on a cutover of old-growth cedar–hemlock forest. Current-year leader growth and foliar vector analyses showed that the trees responded to both treatments during the first growing season with a doubling or tripling of growth rates and improved nutrition. The apparent problem of insufficient sulphur following nitrogen and phosphorus fertilization was not seen in trees treated with sludge. There were no apparent problems in micronutrient supply in these plantations. The extensive area of checked plantations on northern Vancouver Island present an opportunity for the disposal of sewage sludge.

Root systems of older immature hemlock, cedar, and Douglas-fir

1987 ◽  
Vol 17 (11) ◽  
pp. 1348-1354 ◽  
Author(s):  
S. Eis
Keyword(s):  
Root Systems ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Organic Horizon ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Absorbing Roots

Root systems of eight western hemlock (Tsugaheterophylla (Raf.) Sarg.), eight western red cedar (Thujaplicata Donn.), and six Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees, average age about 50 years, average dbh 26.3 cm, were hydraulically excavated. The sizes and shapes of the root systems are given and the root systems and roots are described. Fresh and dry weights of roots of all vegetation averaged 36 and 14 t/ha and were similar for all three species. Fine absorbing roots were distributed mainly in the organic horizon and immediately below it, i.e., in the top 10 or 15 cm of the soil; their turnover appears rapid. Their ovendry weight averaged 210 g/m2 and their length averaged 4 km/m2.

Root Grafts and their Silvicultural Implications

1972 ◽  
Vol 2 (2) ◽  
pp. 111-120 ◽  
Author(s):  
S. Eis
Keyword(s):  
Root System ◽  
Vancouver Island ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Slow Recovery ◽  
Red Cedar ◽  
Western Red Cedar ◽  
Root Grafts

Many trees in stands of Douglas fir, western hemlock and western red cedar on Vancouver Island were joined by functional grafts. In a partially cut stand, 45% of the stumps showed evidence of continued growth and half of these (23%) were still growing vigorously more than 22 years after logging. On experimentally detopped trees, growth extended several meters up the bole. Dominant trees usually supported the growth of the root system and lower boles of grafted suppressed trees.Translocation through grafts may partially explain the frequent stagnation and slow recovery of stands after thinning from above, and may be involved in the usually rapid increase of growth after thinning from below. It is probably a contributing factor in establishing dominance and determining mortality in overtopped trees. In species that graft freely, the use of silvicides in spacing and thinning treatments should be restricted to young stands before grafts are established.

Sign in / Sign up

Export Citation Format

Share Document