Bulldozing stumps and nitrogen fertilization affect growth of Douglas-fir seedlings

1988 ◽  
Vol 18 (6) ◽  
pp. 803-806 ◽  
Author(s):  
W. G. Thies ◽  
E. E. Nelson

Eight treatments involving stump removal by bulldozing in combination with nitrogen fertilization were applied to 0.04-ha circular plots in a clear-cut on the Olympic Peninsula, Washington. Treatments included stump removal (either all stumps removed or the plot left undisturbed) and broadcast fertilization with ammonium nitrate (0, 336, 672, or 1345 kg N ha−1). Diameter at breast height and height of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings, planted several months after treatment, were recorded five and eight seasons after outplanting. The results showed that either bulldozing stumps from the site or fertilizing with ammonium nitrate increased growth of seedlings through their eighth growing season. After eight growing seasons, bulldozing had increased seedling height by 23% and diameter at breast height by 43%; fertilizing produced increases of 13% in height and 17% in diameter at breast height.

1992 ◽  
Vol 16 (3) ◽  
pp. 146-150
Author(s):  
L. E. Nelson ◽  
G. L. Switzer

Abstract Nine-year-old planted sweetgum (Liquidambar styraciflua L.) consisting of four half-sib seed sources were refertilized with nitrogen in 1981 at the beginning of the tenth field-growing season. Increases in periodic annual height, diameter at breast height, basal area, stem volume (ob),and woody biomass increments of all four half-sib seed sources from applied nitrogen were observed during the 9 years following application. Periodic annual stem volume (ob) increments averaged over all half-sib seed sources were 120, 152, 192, and 266 ft³/ac/yr for the 0, 89, 178, and356 lb/ac N rates, respectively. The half-sib seed sources from alluvial sites were superior to those from upland sites in terms of productivity and response to N. The response of all half-sibs to N was immediate, occurring during the year of application; however, the increased growth ratesdue to N persisted for only 3 years. This suggests that on responsive sites, applications of N may be necessary every fourth year to maintain maximum growth rates. South. J. Appl. For. 16(3):146-150.


1999 ◽  
Vol 29 (1) ◽  
pp. 124-134 ◽  
Author(s):  
Shannon M Hagerman ◽  
Melanie D Jones ◽  
Gary E Bradfield ◽  
M Gillespie ◽  
D M Durall

The mycelium extending from ectomycorrhizal fine roots is thought to be an important inoculum source for outplanted seedlings. The purpose of this study, carried out at a subalpine forest in British Columbia, was to investigate the effect of three different clear-cut sizes: 0.1, 1.0, and 10 ha, on the persistence and diversity of ectomycorrhizae. Over the course of the study, a total of 39 distinct mycorrhizal types were observed. The dominant types matched descriptions of E-strain mycorrhizae and of mycorrhizae formed by Cenococcum spp., two types of Lactarius spp., Piloderma spp., Hebeloma spp., Amphinema spp., and Cortinarius spp. One growing season after tree removal, there were no differences between the treatments in the numbers of active fine roots at any location nor were there any effects on the diversity of ectomycorrhizae with treatment. Two and three growing seasons after logging the persistence of some of the main morphotypes differed with treatment. Although there were no differences in the diversity indices at corresponding distances within the different opening sizes, after two and three growing seasons the numbers of active fine roots as well as the diversity of ectomycorrhizae in clearcuts was significantly reduced with distance from the forest edge.


1986 ◽  
Vol 16 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Chao-Hsiung Tung ◽  
Luci Wisniewski ◽  
David R. DeYoe

Survival, phenology, and growth performance of 2 + 0 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and noble fir (Abiesprocera Rehd.) seedlings planted at 1500 m in the Oregon Cascade Range were determined following a lifting on November 7 with 7 months of cold storage or lifting on March 1 with 3 months of cold storage. Storage temperature remained between 1 and 2 °C. There was no difference in Douglas-fir survival attributable to the lifting – cold-storage treatments during the first two growing seasons. The first-season survival of noble fir stored for 7 months was superior to that of those stored for 3 months, but no difference was evident after the second growing season. Timing of bud burst did not differ significantly among treatments for either species. However, the rate of bud burst was significantly greater for noble fir seedlings lifted in November and stored 7 months than for those lifted in March and stored 3 months. No difference in the rate of bud burst was observed between treatments for Douglas-fir. Shoot/root ratio for both species and treatments decreased significantly in the first growing season, but did not change significantly in the second growing season. Regardless of species, no differences were found in height growth or diameter increment between the two lifting – cold-storage treatments for the two consecutive growing seasons. The results suggest that Douglas-fir and noble fir seedlings originating from high-elevation seed sources can be lifted in fall and cold stored for 7 months without adverse effects on seedling performance.


2000 ◽  
Vol 15 (1) ◽  
pp. 34-36 ◽  
Author(s):  
James S. Hadfield ◽  
Paul T. Flanagan

Abstract Fresh attacks of Douglas-firs (Pseudotsuga menziesii) by Douglas-fir beetles (Dendroctonus pseudotsugae) were found in a campground that had trees pruned to remove Douglas-fir dwarf mistletoe (Arceuthobium douglasii) infections. All Douglas-firs with a diameter at breast height (dbh) of at least 12.7 cm were examined. Beetle attacks were found on 41% of the pruned trees and 5% of the unpruned trees. Among pruned trees, both the average number of branches pruned and the average dbh were greater in trees attacked by Douglas-fir beetles than in unattacked trees. West. J. Appl. For. 15(1):34-36.


1987 ◽  
Vol 17 (3) ◽  
pp. 236-241 ◽  
Author(s):  
Douglas A. Maguire ◽  
David W. Hann

Two basic taper models were analyzed for their ability to predict sapwood area at crown base. Sapwood areas were estimated on stem cross sections by measuring sapwood radii on the longest and perpendicular to longest axes and by assuming conformity to an ellipse. These data were collected on 2 to 14 points along the stems of 72 Douglas-fir trees in southwestern Oregon. Across the range in diameter at breast height, total height, and height to crown base, quadratic–quadratic segmented polynomials (T. A. Max and H. E. Burkhart. 1976. For. Sci. 25: 283–289) provided more consistent monotonie taper from breast height to crown base than F. A. Bennett and B. F. Swindel models (1972. USDA For. Serv. Res. Note SE-179). A model for predicting breast height sapwood area from only diameter at breast height, total height, and height to crown base is also presented.


1984 ◽  
Vol 14 (6) ◽  
pp. 952-955 ◽  
Author(s):  
H. J. Barclay ◽  
H. Brix

The effects of two sources of nitrogen fertilizer applied at rates of 224 and 448 kg N/ha on growth of a thinned and unthinned 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand were studied. Ammonium nitrate yielded higher growth of diameter and volume than did urea over a 9-year period, particularly with thinning. Height growth was not affected by nitrogen source. The efficiency of nitrogen fertilization in terms of stem volume response per kilogram of nitrogen applied was greatest with ammonium nitrate in thinned plots. Tree mortality increased substantially with level of fertilization for both sources, and decreased markedly with thinning.


1998 ◽  
Vol 28 (1) ◽  
pp. 74-78 ◽  
Author(s):  
William Scott ◽  
Rodney Meade ◽  
Richard Leon ◽  
David Hyink ◽  
Richard Miller

Test plantations were established in western Washington and Oregon to compare tree growth at six initial planting densities ranging from 300 to 2960 trees/ha (120 to 1200/acre). A size-density relation was visually apparent 3 to 4 years after planting. Inventory data from the oldest 11 trials (5 or 6 years after planting) showed that initial spacing strongly influenced early growth of coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii). Average height and diameter at breast height were progressively larger as planting density increased; at the widest spacing (lowest stand density), average height was 75% and average diameter at breast height was 67% of that at the closest spacing. We have no firm explanation for the early faster tree growth at close spacings. Trees planted at 2960 trees/ha (1200 trees/acre) attained breast height (1.3 m) 2 years earlier than trees planted at a density of 300/ha (120/acre). This finding has practical significance to current efforts to achieve early establishment of plantations.


1979 ◽  
Vol 9 (3) ◽  
pp. 362-368
Author(s):  
J. R. McClenahen ◽  
R. J. Hutnik

Survival, height growth, and abundance of Prunusserotina Ehrh. and other species of tree reproduction were studied during two growing seasons after the trees were cut to residual basal areas of 0 (clear-cut), 16 (partial cut), and 28 (uncut) m2/ha. Portions of each cutting treatment were fenced to exclude deer and (or) amended with 0.91 t/ha of dolomitic limestone. Survival of advance P. serotina seedlings was best among initially older, taller stems. Mortality among 1st-year P. serotina seedlings was higher on clear-cut and uncut plots than on partially cut plots, but cutting had no effect on survival of seedlings older than 2 years. Acersaccharum Marsh, survival was poorest on clear-cuttings. The intermediate level of cutting initially favored a greater abundance of more species than either clear-cutting or no cutting. Rates of height growth of dominant P. serotina seedlings were greatest on clear-cuttings, less on partially cut plots, and lowest in uncut plots. Browsing by deer had a large but statistically nonsignificant effect on height of dominant reproduction after 6 years. Slash generally reduced abundance but enhanced height growth of seedlings. Overall, partial (shelterwood) cutting appeared to be a viable alternative to clear-cutting as a means for regenerating even-aged Allegheny hardwood stands.


1994 ◽  
Vol 24 (2) ◽  
pp. 234-239 ◽  
Author(s):  
Walter G. Thies ◽  
Earl E. Nelson ◽  
Darlene Zabowski

A 2 × 4 set of factorial treatments of stump removal in combination with nitrogen fertilization was applied to 0.04-ha circular plots within a clearcut on the west slope of the Cascade Range (44°21′N, 122°39′W). Treatments included stump removal (either all stumps removed or the plot left undisturbed) and broadcast fertilization with ammonium nitrate (0, 336, 672, or 1345 kg N•ha−1). Diameter at breast height and height of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings, planted 4 months after treatment, were recorded five and nine seasons after outplanting. Soil bulk density in the upper 20 cm was measured with a single-probe neutron densimeter. Stump removal reduced the number of seedlings killed by laminated root rot (Phellinusweirii (Murr.) Gilb.) but had no significant effect on seedling growth. Stump removal increased soil bulk density only 7% as measured 9.7 years after treatment. Fertilization increased the growth in diameter at breast height, and height growth of the seedlings. Elevated total soil nitrogen could still be detected on fertilized, nonstumped plots 9.7 years after treatment.


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