Undercutting conifer seedlings: effect on morphology and field performance on droughty sites

1987 ◽  
Vol 17 (1) ◽  
pp. 40-46 ◽  
Author(s):  
S. D. Hobbs ◽  
S. G. Stafford ◽  
R. L. Slagle
Keyword(s):  
Ponderosa Pine ◽  
Treatment Effects ◽  
Morphological Characteristics ◽  
Field Performance ◽  
Douglas Fir ◽  
Seedling Morphology ◽  
Significant Treatment ◽  
Air Temperatures ◽  
Sufficient Magnitude ◽  
Morphological Differences

Bareroot 2-0 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and ponderosa pine (Pinusponderosa Dougl. ex Laws.) seedlings were subjected to five undercutting treatments, which varied by number and depth of undercut and seedling phenology at time of treatment, so that morphological characteristics at lifting and field performance 4 years after planting on droughty south slopes in southwest Oregon could be evaluated. All undercutting treatments significantly reduced seedling top growth, but changes in root system morphology depended upon treatment severity and species. Treatment effects were generally more pronounced in ponderosa pine than Douglas-fir. Multivariate analysis of variance showed significant treatment effects for both species based on seedling morphology at lifting, but discriminant analyses revealed that these differences existed primarily between undercut seedlings, regardless of undercutting treatment, and controls. In Douglas-fir this separation was largely due to differences in seedling height and in ponderosa pine it was due to differences in tap root biomass. However, no treatment effects were detectable 4 years after outplanting for either species despite record high air temperatures during the first growing season, suggesting that morphological differences at lifting were probably not of sufficient magnitude to affect field performance.

Early Development of Three Douglas-Fir Stocktypes on a Droughty Skeletal Soil

1989 ◽  
Vol 4 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Stephen D. Hobbs ◽  
Michael S. Crawford ◽  
Beverly A. Yelczyn
Keyword(s):  
Surface Soil ◽  
Morphological Characteristics ◽  
Field Performance ◽  
Douglas Fir ◽  
Root Characteristics ◽  
Relative Growth ◽  
Seedling Root ◽  
Absolute Growth ◽  
Southwest Oregon ◽  
Better Than

Abstract Three stocktypes of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) were planted in a droughty, skeletal soil in southwest Oregon. After 5 years, container-grown plugs and plug-1 transplants survived significantly better than 2-0 bareroots. Seedling root systems were largely confined to the surface soil, with relatively little development upslope or deeper than 15 cm. Stocktype morphology differed significantly at planting. However, annual absolute growth, annual relative growth, and shoot and root characteristics did not differ significantly after 5 years. These results suggest that, on similar sites, seedling morphological characteristics within the range of those measured in this study may not affect growth and that stocktype designation along may not be adequate for predicting field performance. West. J. Appl. For. 4(1):21-24, January 1989.

scholarly journals Effects of Douglas-fir 2+0 seedling morphology on field performance

New Forests ◽  
1993 ◽  
Vol 7 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Alan J. Long ◽  
Byron D. Carrier
Keyword(s):  
Field Performance ◽  
Douglas Fir ◽  
Seedling Morphology

scholarly journals Thirteen-Year Height and Diameter Growth of Douglas-Fir Seedlings under Alternative Regeneration Cuts in Pacific Northwest

2011 ◽  
Vol 26 (2) ◽  
pp. 57-63 ◽  
Author(s):  
Tzeng Yih Lam ◽  
Douglas A. Maguire
Keyword(s):  
Pacific Northwest ◽  
Treatment Effects ◽  
Basal Area ◽  
Height Growth ◽  
Douglas Fir ◽  
Diameter Growth ◽  
Treatment Level ◽  
Growth Responses ◽  
Significant Treatment ◽  
Ecosystem Responses

Abstract Interest in managing Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) forests in the Pacific Northwest under silvicultural systems other than traditional clearcutting has prompted research on the efficacy of alternative systems for successful regeneration and sustained timber productivity of Douglas-fir. The College of Forestry Integrated Research Project, implemented by Oregon State University, was established to compare various ecosystem responses and public perceptions among treatments implemented under clearcutting, shelterwood-with-reserves, and group selection silvicultural systems. The objective of this analysis was to quantify the following three responses of planted Douglas-fir seedlings to initial regeneration cuts: cumulative 13-year height growth (H13yr; 1992–2004), cumulative 13-year diameter growth (D13yr; 1992–2004), and most recent 5-year height growth (ΔH5yr; 2000–2004). Differences in variability of overstory density at the treatment level led to significant differences in the variance of understory growth responses. After accounting for heterogeneous variance, analysis of variance indicated significant treatment effects for all three responses. Treatment effects were explained by the decline in H13yr, D13yr, and ΔH5yr with increasing overstory competition as represented by basal area of residual trees immediately after harvesting (initial basal area). Predicted height:diameter ratio of Douglas-fir seedlings increased as IBA increased. Under regeneration methods that retain a portion of the overstory, a residual overstory with basal area <80 ft2/ac allows establishment, growth, and continued survival of Douglas-fir regeneration during the 13 years following harvest.

Nursery and field fertilization of 2 + 0 ponderosa pine seedlings: the effect on morphology, physiology, and field performance

1990 ◽  
Vol 20 (11) ◽  
pp. 1766-1772 ◽  
Author(s):  
J. F. Gleason ◽  
M. Duryea ◽  
R. Rose ◽  
M. Atkinson
Keyword(s):  
Ponderosa Pine ◽  
Field Performance ◽  
Frost Damage ◽  
The Other ◽  
Seedling Morphology ◽  
N Application ◽  
Foliar N ◽  
Growing Seasons ◽  
N Concentration ◽  
Seed Zone

Ponderosa pine (Pinusponderosa Laws.) from two seed zones in central Oregon were grown at two nurseries where they were subjected to fall applications of N, N + K, or no fertilizer. For one seed zone, foliar N concentration increased from 1.47 to 1.53% for the N application and to 1.57% for N + K application. For the other seed zone, seedlings did not show any differences in foliar N after nursery fertilization. Seedlings that received the N application appeared to be less susceptible to frost damage, but nursery fertilization had little or no effect on seedling morphology or bud break. One month after outplanting 2 + 0 seedlings back to their respective seed-zone sites, slow-release fertilizer pellets were placed 10–13 cm from half the trees. Soils at the outplanting sites differed in mineral content, percent organic matter, and pH. The nursery-fertilized seedlings with increased N concentration grew more than control seedlings during the first season. Field-fertilized seedlings at the less fertile field site grew more in the second and third growing seasons, indicating that field fertilization after outplanting is more effective on nutrient-poor sites. Soil fertility had a greater impact on seedling performance than did nursery- and field-fertilizer treatments. At the less fertile site, N concentration decreased by 14% during the first growing season and increased by 22% during the second season, whereas at the more fertile site it increased during both the first season (12%) and the second season (6%). Seedlings at the more fertile site almost doubled in height in the 3rd year and were more than 20 cm taller than those at the other site.

Multicentury history of western spruce budworm outbreaks in interior Douglas-fir forests near Kamloops, British Columbia

2006 ◽  
Vol 36 (7) ◽  
pp. 1758-1769 ◽  
Author(s):  
Rochelle Campbell ◽  
Dan J Smith ◽  
André Arsenault
Keyword(s):  
British Columbia ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Survival Rates ◽  
Spruce Budworm ◽  
Douglas Fir ◽  
Western Spruce Budworm ◽  
Air Temperatures ◽  
Forest Sites ◽  
History Of

Western spruce budworm (Choristoneura occidentalis Freeman) is a native defoliator of forests in the interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) forests of British Columbia, Canada. Dendrochronological techniques and the software program OUTBREAK were used to reconstruct a defoliation history of Douglas-fir for 19 forest sites near Kamloops in central British Columbia. By comparing the radial-growth response of ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) with that of Douglas-fir growing in nearby but separate stands, eight western spruce budworm outbreaks over the past 300 years were distinguished. Although there is considerable variation in the timing and duration of these western spruce budworm events at the stand level, synchronous outbreaks have occurred in approximately 30- to 43-year cycles. Spectral analyses of a composite time series from all stands showed similar and consistent intervals between outbreaks. Climatic variation appears to have been important to budworm outbreaks in the 20th century. Notable outbreaks tended to occur during years with average spring air temperatures following winters with less than average precipitation. Based on this finding, it is proposed that with high over-winter survival rates and a longer growing season, the duration of outbreaks may increase in the future.

scholarly journals The Hungry Bob Fire & Fire Surrogate Study: A 20-Year Evaluation of the Treatment Effects

Forests ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 15
Author(s):  
George McCaskill
Keyword(s):  
Ponderosa Pine ◽  
Treatment Effects ◽  
The United States ◽  
Douglas Fir ◽  
Diameter Growth ◽  
Tree Crown ◽  
Fuels Reduction ◽  
Tree Crowns ◽  
Burn Unit ◽  
Burn Units

The Hungry Bob fuels reduction project was part of a 12-site National Fire and Fire Surrogate (FFS) network of experiments conducted across the United States from the late 1990s through the early 2000s to determine the regional differences in applying alternative fuel-reduction treatments to forests. The Hungry Bob project focused on restoration treatments applied in low elevation, dry second-growth ponderosa pine (Pinus ponderosa subsp. ponderosa (Douglas ex C. Lawson) and Douglas-fir (Pseudotsuga menziesii subsp. glauca (Beissn.) Franco forests of northeastern Oregon. Treatments included a single entry thin from below in 1998, a late season burn in 2000, a thin (1999) followed by burning (2000), and a no-treatment control. This paper represents results 20 years after treatments and focuses on the treatment effects upon tree diameter growth, crown health, and ladder fuel conditions within the dry eastside stands. The Thin + Burn units produced the best diameter growth in ponderosa pine trees, whereas the Thin units had the best growth for Douglas-fir. The Burn treatment did not improve diameter growth over the Controls. The Thin + Burn treatments also produced trees with the highest tree crown ratios. The Burn unit trees had lower crown ratios compared to the Control trees. The crown reduction (reduction in tree crown ratio since 2004) was largest in the Burn-only units and smallest in the Thin + Burn units. Finally, the heights to the lower tree crowns were highest in the Thin + Burn trees and lowest in the Burn unit trees. Based upon the 20-year responses, the Thin + Burn treatments produced the best conditions for stand growth, while limiting fire stress upon residual tree crowns. It also proved most effective at reducing ladder fuels as represented by higher tree crown heights.

scholarly journals Douglas Fir and Ponderosa Pine Seed Dormancy as Regulated by Grassland Seedbed Conditions

2004 ◽  
Vol 57 (6) ◽  
pp. 661 ◽  
Author(s):  
Yuguang Bai ◽  
Don Thompson ◽  
Klaas Broersma
Keyword(s):  
Seed Dormancy ◽  
Ponderosa Pine ◽  
Douglas Fir

Aboveground Field Performance of Douglas-Fir Heartwood Subjected to Combinations of Glycerol, Boron, and Thermal Modification

2021 ◽  
Vol 71 (1) ◽  
pp. 42-45
Author(s):  
Li Yan ◽  
Jed Cappallazzi ◽  
Jeffrey J. Morrell
Keyword(s):  
Field Performance ◽  
Decay Resistance ◽  
Douglas Fir ◽  
Thermal Modification ◽  
Site Conditions ◽  
Consistent Effect ◽  
Wood Protection ◽  
Copper Azole ◽  
Better Than

Abstract The effect of pretreatment with either boron or glycerol followed by thermal modification on the durability of Douglas-fir heartwood was evaluated in an American Wood Protection Association ground proximity test in Hilo, Hawaii. Non–thermally modified samples were generally more heavily decayed than any of the modified woods, but there was no consistent effect of different thermal modification conditions on decay resistance. Thermally modified woods tended to perform better than untreated timbers but not as well as copper azole–treated Douglas-fir heartwood lumber in test at the same site. The results are discussed in relation to how the extreme site conditions might have made it difficult for thermally modified materials to perform.

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