Investigating Relationships between Nutrient Concentrations, Stem Sinuosity, and Tree Improvement in Douglas-Fir Stands in Western Washington

Stem sinuosity is a deformation that occurs in Douglas-fir and other tree species. Nutritional deficiencies, such as those of copper, zinc, boron, and calcium have been positively associated with increased stem form deformities. The objective of this study was to analyze available soil and total foliar concentrations of sinuous Douglas-fir stands and determine if these data provided insights into the role of nutrients on sinuosity across different sites. Relationships among genetic gain levels across different sites were also assessed to evaluate whether trees selected for growth and form were better at mobilizing and sequestering nutrients in soils or needles. As data collected were multivariate, Mantel test and permutational multivariate analysis of variance (PERMANOVA) were used to study effects of site, genetic gain levels on soil, and foliar nutrients, with ordinations used to visualize trends. The stands were found to be deficient in boron and calcium, and moderately deficient with respect to zinc and nitrogen. Combining foliar data with soil nutrients revealed that there was differential uptake of these nutrients as compared to other more abundant micronutrients. Results of univariate and multivariate analyses showed that site was the most important predictor, which explained variation among soil nutrient concentrations. Genetic gain level was a significant predictor for variation among soil nutrients; however, not significantly for foliar concentrations according to multivariate analyses. Trends in the data indicate that proper genetic selection could reduce sinuosity while also increasing growth. The results of this study support the contention that no one single factor can explain stem sinuosity. It is likely that sinuous growth in trees is caused by a combination of unbalanced nutrient concentrations and metal deficiencies, as were seen in this study, in addition to genetic, environmental, and physiological factors

Effects of Thinning and Nitrogen Fertilization on Sugars and Terpenes in Douglas-Fir Vascular Tissues: Implications for Black Bear Foraging

The chemical constituents of coniferous vascular tissues play a role in bear forage selection. In particular, bear foraging preferences are related to the concentrations of simple sugars (nonstructural carbohydrates) and terpenes in the forage. Analyses of vascular tissue samples from trees collected in test plots indicted that both thinning and fertilization caused the sugar concentration of vascular tissues in the lower bole to increase. However, these treatments had no effect on the concentrations of hydrocarbon monoterpenes, oxygenated monoterpenes, or sesquiterpenes. These results may explain the observations that black bears prefer to forage in thinned and fertilized stands

Tree Species Detection Accuracies Using Discrete Point Lidar and Airborne Waveform Lidar

Species information is a key component of any forest inventory. However, when performing forest inventory from aerial scanning Lidar data, species classification can be very difficult. We investigated changes in classification accuracy while identifying five individual tree species (Douglas-fir, western redcedar, bigleaf maple, red alder, and black cottonwood) in the Pacific Northwest United States using two data sets: discrete point Lidar data alone and discrete point data in combination with waveform Lidar data. Waveform information included variables which summarize the frequency domain representation of all waveforms crossing individual trees. Discrete point data alone provided 79.2 percent overall accuracy (kappa = 0.74) for all 5 species and up to 97.8 percent (kappa = 0.96) when comparing individual pairs of these 5 species. Incorporating waveform information improved the overall accuracy to 85.4 percent (kappa = 0.817) for five species, and in several two-species comparisons. Improvements were most notable in comparing the two conifer species and in comparing two of the three hardwood species

Effect of Rotation Age and Thinning Regime on Visual and Structural Lumber Grades of Douglas-Fir Logs

Douglas-fir, the most important timber species in the Pacific Northwest, US (PNW), has high stiffness and strength. Growing it in plantations on short rotations since the 1980s has led to concerns about the impact of juvenile/mature wood proportion on wood properties. Lumber recovered from four sites in a thinning trial in the PNW was analyzed for relationships between thinning regime and lumber grade yield. Linear mixed-effects models were developed for understanding how rotation age and thinning affect the lumber grade yield. Log small-end diameter was overall the most important for describing the presence of an appearance grade, generally exhibiting an indirect relationship with the lower quality grades. Stand Quadratic Mean Diameter (QMD) was found to be the next most uniformly important predictor, its influence (positive or negative) depending on the lumber grade. For quantity within a grade, as log small-end diameter increased, the quantity of the highest grade increased, while decreasing the quantity of the lower grades differentially. Other tree and stand attributes were of varying importance among grades, including stand density, tree height, and stand slope, but logically depicted the tradeoffs or rebalancing among the grades as the tree and stand characteristics change. Structural lumber grade presence was described best by acoustic wave flight time, log position (decreasing presence in upper logs), and an increasing presence with rotation age. A smaller set of variables proved useful for describing quantity within a structural grade. Forest managers can use these results in planning to best capture value in harvesting, allowing them to direct raw materials (logs) to appropriate manufacturing facilities given market demand

Thinning Treatments Reduce Deep Soil Carbon and Nitrogen Stocks in a Coastal Pacific Northwest Forest

Forests provide valuable ecosystem and societal services, including the sequestration of carbon (C) from the atmosphere. Management practices can impact both soil C and nitrogen (N) cycling. This study examines soil organic C (SOC) and N responses to thinning and fertilization treatments. Soil was sampled at an intensively managed Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation in north-western Oregon, USA. Management regimes—thinning, fertilization plus thinning, and no (control) treatment—were randomly assigned to nine 0.2-ha plots established in 1989 in a juvenile stand. Prior to harvest, forest floor and soil bulk density and chemical analysis samples were collected by depth to 150 cm. During a single rotation of ~40 years, thinning treatments significantly reduced SOC and N stocks by 25% and 27%, respectively, compared to no treatment. Most of this loss occurred in deeper soil layers (below ~20 cm). Fertilization plus thinning treatments also reduced SOC and N stocks, but not significantly. Across all management regimes, deeper soil layers comprised the majority of SOC and N stocks. This study shows that: (1) accurately quantifying and comparing SOC and N stocks requires sampling deep soil; and (2) forest management can substantially impact both surface and deep SOC and N stocks on decadal timescales

Bio-methanol potential in Indonesia: Forest biomass as a source of bio-energy that reduces carbon emissions

Since Indonesia has significant land area in different forest types that could be used to produce biofuels, the potential to sustainably collect and convert forest materials to methanol for use in energy production was examined. Using the annually available aboveground forest biomass, from 40 to 168 billion l of bio-methanol could be produced for use as a transportation fuel and/or to supply fuel cells to produce electricity. When a lower forest biomass availability estimate was used to determine how much electricity (methanol fed into fuel cells) could be produced in Indonesia, more than 10 million households or about 12,000 villages (20% of the total rural villages in Indonesia) would be supplied annually with electricity. Collecting forest biomass at the higher end of the estimated available biomass and converting it to methanol to supply fuel cells could provide electricity to more than 42 million households annually. This would be approximately 52,000 villages, or 86% of the total rural villages in Indonesia. When electricity is produced with bio-methanol/fuel cells, it could potentially supply from half to all of the current electricity consumed in Indonesia. By generating electricity using bio-methanol/fuel cells instead of from fossil fuels, from 9 to 38% of the total carbon currently emitted each year in Indonesia could be avoided. In contrast, substituting this same amount of bio-methanol for gasoline could provide all of the annual gasoline needs of Indonesia and contribute towards reducing their carbon emissions by about 8-35%.Aboveground forest biomass Forest residues/wastes Bio-methanol Electricity production Transportation fuels Carbon emissions

Nontraditional Use of Biomass at Certified Forest Management Units: Forest Biomass for Energy Production and Carbon Emissions Reduction in Indonesia

Biomass conversion technologies that produce energy and reduce carbon emissions have become more feasible to develop. This paper analyzes the potential of converting biomass into biomethanol at forest management units experiencing three forest management practices (community-based forest management (CBFM), plantation forest (PF), and natural production forest (NPF)). Dry aboveground biomass collected varied considerably: 0.26–2.16 Mg/ha/year (CBFM), 8.08–8.35 Mg/ha/year (NPF), and 36.48–63.55 Mg/ha/year (PF). If 5% of the biomass was shifted to produce biomethanol for electricity production, the NPF and PF could provide continuous power to 138 and 2,762 households, respectively. Dedicating 5% of the biomass was not a viable option from one CBFM unit. However, if all biomasses were converted, the CBFM could provide electricity to 19–27 households. If 100% biomass from two selected PF was dedicated to biomethanol production: (1) 52,200–72,600 households could be provided electricity for one year; (2) 142–285% of the electricity demand in Jambi province could be satisfied; (3) all gasoline consumed in Jambi, in 2009, would be replaced. The net carbon emissions avoided could vary from 323 to 8,503 Mg when biomethanol was substituted for the natural gas methanol in fuel cells and from 294 to 7,730 Mg when it was used as a gasoline substitute

Biomass and Stand Characteristics of a Highly Productive Mixed Douglas-Fir and Western Hemlock Plantation in Coastal Washington

Aboveground biomass predictive equations were developed for a highly productive 47-year-old mixed Douglas-fir and western hemlock stand in southwest Washington State to characterize the preharvest stand attributes for the Fall River Long-Term Site Productivity Study. The equations were developed using detailed biomass data taken from 31 Douglas-fir and 11 western hemlock trees within the original stand. The stand had an average of 615 live trees per hectare, with an average dbh of 35.6 cm (39.1 cm for Douglas-fir and 33.3 cm for western hemlock) and an average total tree height of 31.6 m (32.8 m for Douglas-fir and 30.2 m for western hemlock). Equations developed were of the form In Y = b(1) + b(2) In dbh, where Y = biomass in kg, dbh = diameter in cm at 1.3 m height, b(1) = intercept, and b(2) = slope of equation. Each tree part was estimated separately and also combined into total aboveground biomass. The total aboveground biomass estimation equations were In Y = -0.9950 + 2.0765 In dbh for Douglas-fir, and In Y = -1.6612 + 2.2321 In dbh for western hemlock. The estimate of the aboveground live-free biomass was of 395 Mg ha(-1) (235 Mg ha(-1) for Douglas-fir and 160 Mg ha(-1) for western hemlock), with 9.5, 29.3, 12.9, 308, and 32.7 Mg ha(-1) in the foliage, live branches, dead branches, stem wood, and stem hark, respectively. When compared with biomass estimates from six other studies, ranging in age from 22 to 110 years and from 96.3 to 636 Mg ha(-1), the biomass of the Fall River site was relatively high for its age, indicating very high productivity