Growth Of Fir Research Articles

Effects of root trenching of overstorey Norway spruce (Picea abies) on growth and biomass of underplanted beech (Fagus sylvatica) and Douglas fir (Pseudotsuga menziesii) saplings

In Central Europe, the conversion of pure Norway spruce stands (Picea abies [L.] Karst.) into mixed stands with beech (Fagus silvatica L.) and other species like e.g. Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) is accomplished mainly by underplanting of seedlings beneath the canopy of overstorey spruce trees after partial cutting treatments what means exposure to shade and below-ground root competition by the overstorey to the seedlings. Particularly about the second factor, our knowledge is limited. Therefore, we carried out a below-ground competition exclusion experiment by root trenching and investigated the effects on soil resources, growth, and biomass partitioning of underplanted beech and Douglas fir saplings under target diameter and strip cutting treatments. The exclusion of overstorey root competition by trenching increased the soil water potential in the second year that had a fairly dry growing season and led to significantly higher foliar concentrations of most nutrients, particularly in Douglas fir, indicating an amended nutrient supply. Both improvements were accompanied by an increase in length and diameter increment of the underplanted saplings, appearing in both species only after having surpassed a species-specific threshold light value (Douglas fir 16% of above canopy radiation, beech 22%). We also found significant interactions between trenching and light for specific fine root length and further biomass and morphological parameters. Judged by the much steeper increase in height and diameter growth with increasing light after release from below-ground competition, Douglas fir saplings appeared to be more sensitive to root competition than beech saplings what conforms to older findings for beech. According to our results, a strip cutting seems to be more appropriate than a target diameter cutting treatment to replace a pure spruce stand by a mixed stand with beech and Douglas fir.

Grafting Fraser Fir (Abies fraseri): Effect of Scion Origin (Crown Position and Branch Order)

Success and subsequent growth of fraser fir [Abies fraseri (Pursh) Poir.] cleft grafts were studied in relation to origin and type of scion material in the tree crown. First- and second-order shoots (current-year) were collected from five zones in the crown, ranging from top to bottom, and grafted to 5-year-old fraser fir transplants in April. Success rates were similar for first- and second-order scions, whereas budbreak and subsequent growth were best for first-order scions. In general, results were best for first-order scions taken from the upper crown. Plagiotropism of grafts was similar for all crown zones and shoot types.

Effects of climate on diameter growth of co-occurring Fagus sylvatica and Abies alba along an altitudinal gradient

In high-elevation forests, growth is limited by low temperatures, while in Mediterranean climates drought and high temperatures are the main limiting factors. Consequently, the climate-growth relationships on Mont Ventoux, a mountain in the Mediterranean area, are influenced by both factors. Two co-occurring species were studied: silver fir (Abies alba Mill.) and common beech (Fagus sylvatica L.), whose geographical distribution depends on their low tolerance to summer drought at low altitude/latitude, and low temperatures (late frost and short length of the growing season) at high altitude/latitude. Firs and beeches distributed along an elevational gradient were investigated using dendroecological methods. Silver fir growth was found to be more sensitive to summer water stress than beech. On the other hand, beech growth was more impacted by extreme events such as the 2003 heat wave, and negatively related to earlier budburst, which suggests a higher sensitivity to late frost. These results are confirmed by the different altitudinal effects observed in both species. Beech growth decreases with altitude whereas an optimum of growth potential was observed at intermediate elevations for silver fir. Recent global warming has caused a significant upward shift of these optima. As found for the period 2000–2006, rising temperatures and decreasing rainfall may restrain growth of silver fir. If these trends continue in the future beech might be favored at low altitudes. The species will have a reduced capacity to migrate to higher altitudes due to its sensitivity to late frosts, although an upward shift of silver fir is likely.

Returns from the Management of Noble Fir Stands for Bough Production and Sawtimber

Abstract Noble fir (Abies procera Rehder) bough harvest has been part of the nontimber forest products industry in the Pacific Northwest for decades. The boughs are used for seasonal decorations and command a higher pricethan most other decorative bough species. However, noble fir boughs that are harvested in the region have been merely a byproduct of noble fir plantations managed for timber products. This article presents the results of a study assessing the financial desirability of managing noble fir plantationsin the southern Cascade Mountains of Washington State for the production of both timber and bough products. The Landscape Management System software program was used to simulate the growth of noble fir in four different plant associations on the Gifford Pinchot National Forest. Data from recentlyestablished noble fir plantations were used in the simulations. Harvestable bough weights were estimated using a previously published noble fir bough weight model. Comparisons of estimated harvest volumes for sawlogs and noble fir boughs showed positive present net worth (PNW) values for eachstand under a combined timber production and bough harvest scenario and negative PNW values for each stand with a timber production management scenario only. Bough harvest is compatible with other land use activities, and the harvest revenue can cover stand establishment and precommercialthinning costs.

Climaticaly Induced Dynamic of Radial Growth of Siberian Stone Pine and Siberian Fir in the Mountain-Taiga Belt in Ergaki National Park

Climaticaly Induced Dynamic of Radial Growth of Siberian Stone Pine and Siberian Fir in the Mountain-Taiga Belt in Ergaki National Park

Patterns of tree growth in a single tree selection silver fir–European beech forest

The basal area and height growth of trees and saplings in silver fir–European beech single stem selection forest were studied with regard to their social status and crown parameters of size, coverage, shading and vitality. On 24 permanent research plots (20 m × 20 m each) all trees [diameter at breast height (dbh) ≥10 cm] and saplings (≥1.3 m tall and dbh <10 cm) were surveyed. Repeated measurements of dbh (N = 1,608) and height (N = 1,135) 10 years apart enabled the calculation of annual basal area increment (BAI) of trees and saplings, and annual height (HI) increment of saplings. To obtain the growth characteristics for individual trees and saplings, their social status and crown parameters were assessed by rank. In the multivariate general linear model for BAI, social status, crown size and crown coverage of individuals as the predictors, and dbh2 as the covariate, explained 70% of total variability. Similarly, social status, crown size, crown coverage and crown shading had a significant impact on the HI of saplings, explaining 70% of total variability. Among the observed variables, social status determined according to the individual's position in vertical stand structure was, in addition to dbh, the most important predictor for both BAI and HI. Significant differences were observed between the BAI and HI models for the main tree species (European beech and silver fir), indicating their different growth characteristics. The applied method could be used as a supplement to the more widely used approaches for studying basal area and height growth of individual trees in selection forest stands.

Competition and regeneration in quaking aspen-white fir (Populus tremuloides-Abies concolor) forests in the Northern Sierra Nevada, USA

Question: How does competition between quaking aspen (Populus tremuloides) and white fir (Abies concolor) affect growth and spatial pattern of each species? Location: The northern Sierra Nevada, California, USA. Methods: In paired plots in mixed aspen- (n=3) or white fir-dominated (n=2) stands, we mapped trees and saplings and recorded DBH, height, species, and condition and took increment cores. We tallied seedlings by species. Tree ring widths were used as a measure of basal area change over the last decade, and canopy openness was identified using hemispherical photographs. Linear mixed models were used to relate neighborhood indices of competition, stand, and tree-level variables to diameter increment. Spatial patterns of stems were identified using the Neighborhood Density Function. Results: White fir radial growth was higher in aspen- than white fir-dominated plots. Individual-level variables were more important for white fir than for aspen growth, while variables representing competitive neighborhood were important only for aspen. The forest canopy was more open in aspen- than white fir-dominated stands, but ample aspen seedlings were observed in all stands. Canopy stems of aspen and white fir were randomly distributed, but saplings and small trees were clumped. Aspen saplings were repelled by canopy aspen stems. Conclusions: Variation in canopy openness explained more stand–stand variation in white fir than aspen growth, but high light levels were correlated with recruitment of aspen seedlings to the sapling class. Radial growth of aspen was predicted by indices of neighborhood competition but not radial growth of white fir, indicating that spacing and stem arrangement was more important for aspen than white fir growth. Fire suppression has removed a major disturbance mechanism that promoted aspen persistence and reduced competition from encroaching conifers, and current forests favor species that regenerate best by advance regeneration (white fir).

Growth responses of three coexisting conifer species to climate across wide geographic and climate ranges in Yukon and British Columbia

This work aimed to compare radial growth–climate relationships among three coexisting coniferous tree species across a wide geographic and climate range from southern British Columbia (BC) to central Yukon, Canada. Tree-ring data were collected from 20 mature stands of white spruce (Picea glauca), lodgepole pine (Pinus contorta var. latifolia), and subalpine fir (Abies lasiocarpa). Linear relationships between annual growth variation and monthly and seasonal climate were quantified with correlation and regression analyses, and variation in climate–growth responses over a climatic gradient were quantified by regressing growth responses against local mean climatic conditions. Temperatures had more consistent and stronger correlations with growth for all three species than precipitation, but growth–climate responses varied among species and among sites. In particular, pine and fir populations showed different responses between BC and Yukon, whereas spruce showed a more consistent response across the study domain. Results indicate that (1) the response and sensitivity of trees to seasonal climate variables vary among species and sites and (2) winter temperatures prior to growth may have significant impacts on pine and fir growth at some sites. The capacity to adapt to climate change will likely vary among the study species and across climatic gradients, which will have implications for the future management of mixed-species forests in Yukon and BC.

Impact of precommercial thinning on tree growth, lumber recovery and lumber quality in Abies balsamea

Precommercial thinning (PCT) is often used to improve stand growth and value. While PCT may accelerate tree growth and reduce mortality, it may also have a negative effect on product quality. This study examined the effect of moderate and heavy thinning on tree growth, lumber recovery and quality in a natural balsam fir [Abies balsamea (L.) Mill.] PCT trial 35 years after thinning. Compared with the control, the heavy thinning increased merchantable tree diameter, stem volume per tree and lumber volume recovery per tree by 41.1%, 100.9% and 92.7%, respectively, reduced the Select Structural grade (the best grade) recovery by 33.7%. Thinning did not affect the no. 2 and better grade yield. There was a 12.2% and 15.0% difference, respectively, in the lumber bending modulus of elasticity (MOE) and modulus of rupture (MOR) between the control and heavy thinning. Moderate thinning had little impact on the visual grade recovery, lumber bending MOE and MOR. Heavy thinning is recommended if the goal is to get sizeable sawlogs in the shortest time, whereas moderate thinning is preferable if the intention is to minimize the negative effects on lumber quality while retaining modest tree growth and lumber recovery. Overall, PCT of very dense young balsam fir stands appears to be an effective and viable silvicultural treatment.

Impact of mistletoe attack (Viscum album ssp. abietis) on the radial growth of silver fir. A case study in the North of Eastern Carpathians

Viscum album ssp. abietis (Wiesb.) Abrom L. is one of the three subspecies of Viscum album L that is frequently encountered in Romanian forests. The mistletoe has notoriously negative effects on trees and forests health. The mistletoe infections not only reduce both height and diameter growth, it can also cause partial or total die-back of the trees. The present study on the incidence of mistletoe (Viscum album ssp. abietis) on silver fir (Abies alba) increments was carried out in natural stands of the Forest District Gura Humorului (one permanent plot Paltinoasa and one experimental plot Voroneţ), because this location (400-1000 m elevation) is characteristic for pure silver fir stands that can be found on the border of Carpathians Mountains at the contact zone with Suceava plateau. Four classes describing the level of infection were distinguished: no infection, low, moderate and strong infection. As only a few of healthy trees (class 0) were found, the comparison was made on the trees from the 1st class of attack. In parasited silver trees development were distinguished 3 phases: i) phase 1 - from 1920 till 1945 when the trees that nowadays are falling into the 2nd and 3rd class had similar growth with the ones recorded in the 1st class; ii) phase 2 - from 1946 till 1976-1977; during this period the trees had been reducing their growth. The growth of silver fir trees that fall into the 2nd and 3rd classes of parasitism represents 80% of the average growth of 1st class trees; iii) phase 3 - from 1977 till 2007 (with a couple of episodes) when trees growths from 1st, 2nd and 3rd classes of parasitism were clearly differentiated.

Legacy of Insect Defoliators: Increased Wind-Related Mortality Two Decades After a Spruce Budworm Outbreak

Abstract Effects of spruce budworm (Choristoneura fumiferana Clem.) outbreaks on growth and survival of balsam fir (Abies balsamea [L.] Mill.) and spruce (Picea spp.) are well documented, but few studies extend beyond 10 years after defoliation ceased. We used inventory data from 106 permanent sample plots in &amp;gt;50-year-old balsam fir stands in northern New Brunswick, Canada, to determine legacy effects of the 1969–1993 budworm outbreak on stand development up to 29 years after defoliation ceased. Defoliation data were from annual aerial surveys from 1945 to 1993 and plot ground sampling from 1985 to 1993. Plots were stratified into net stand volume development categories (decreasing, stable, and increasing 1985–2005 stemwood volume) and related to outbreak phases (outbreak, direct 1–10 years after defoliation ceased, and legacy &amp;gt;10 years), outbreak severity (1–4 [low], 5–8 [medium], and 9–12 [high] years of defoliation), and stand age (mature and overmature). Stand age was an important factor influencing outbreak severity (e.g., r2 = 0.383, P &amp;lt; 0.01). Trend and rate of volume development over time were related to past outbreak severity and increased rate of postoutbreak wind-related mortality, which peaked at 11 m3/ha/yr 11–15 years after defoliation ceased. Results indicate that aging postoutbreak stands are more vulnerable to wind disturbance events, effecting rapid stand decline.

Growth–climate responses of high-elevation conifers in the central Hengduan Mountains, southwestern China

Improved understanding of tree-growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. We applied dendroclimatological techniques to assess the effects of inter-annual climate variations on radial growth of high-elevation conifers in the central Hengduan Mountains, southwestern China. Eight tree-ring width chronologies of the major tree genera Abies and Picea that are aligned along an elevation gradient from 3200 to 4200 m a.s.l. were developed. Correlation and principal component analyses for the eight chronologies identified three groups of sites, representing different patterns of growth–climate relationships. Correlation and redundancy analyses with regional climate data revealed that radial growth of fir growing at high-elevation sites is enhanced by normal or warm summer temperatures (June and July) during the current growing season. In addition, radial growth of trees growing from high to middle elevations is sensitive to low temperatures during winter season. At low-elevation sites, trees display low sensitivity to temperature variation. However spring moisture availability becomes crucial for radial growth regardless of tree species. High- to middle-elevation conifers in the central Hengduan Mountains may benefit from the current climate warming, especially from rising winter temperatures.

Long-term outcome of precommercial thinning on floristic diversity in north western New Brunswick, Canada

The Green River spacing trials were established between 1959 and 1961 to study the long-term growth and development of balsam fir (Abies balsamea (L.) Mill.) and red spruce (Picea rubens Sarg.) in response to precommercial thinning (PCT). Three nominal spacings (1.2 m, 1.8 m, 2.4 m) and an unthinned control were applied in a randomized complete block design with 5 replicates to regenerating stands, an average of 8 years after harvest. Our study examines floristic diversity associated with these treatments approximately four decades later. Floristic diversity was assessed with several alpha diversity indices as well as multivariate analysis to compare community composition. Specific a-priori contrasts compared plant diversity among a) control and average of the wider spacings (1.8 m and 2.4 m), b) control and the narrowest spacing (1.2 m), and c) the narrowest spacing and the widest spacing. Our results indicate that there were no appreciable differences among the treatments across all measures of plant diversity investigated. As such, we conclude that the forest understory, as represented by the unthinned plots, was analogous in the thinned plots at time of stand maturity. Vegetation response to PCT treatments is inconsistent in the published literature, but this can be attributed to differences in thinning intensities, recovery age or the type of forest ecosystem studied. We conclude that PCT is a variable silvicultural tool that could be used to attain both economic productivity and biodiversity conservation goals.

Growth and health state of silver fir (Abies alba Mill.) in the ridge area of the Jizerské hory Mts.

The silver fir was planted under mountain conditions in order to reveal its response to the addition of finely ground rocks (limestone and amphibolite) mixed with soil into the planting holes. The results document that the increments of the plantations fertilised with amphibolite were higher by 25% on average than those of the control plantations while the increments of the plantations treated with dolomitic limestone were lower by 13%. Generally, as concerns both the plantations with the application of ground rocks and the control ones, the development of the fir plantations in 1994–2007 is considered successful. As the damage by climatic stresses has gradually diminished, the number of dead trees has been decreasing and the height increments have been increasing in the last years, therefore a positive development is to be expected also in future.

Allelochemicals and Activities in a Replanted Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook) Tree Ecosystem

Autotoxicity is a major reason for replant problems in managed tree ecosystems. Studies have related phenolics-based allelochemicals to autotoxicity. We selected a 20-year-old replanted Chinese fir [Cunninghamia lancealata (Lamb.) Hook] tree ecosystem to isolate, identify, determine the biological activity of, and quantify soil phytotoxins. Eight common phenolics (coumarin, vanillin, isovanillin, and p-hydroxybenzoic, vanillic, benzoic, cinnamic, and ferulic acids), friedelin, and a novel cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane-2,5-diketone) were obtained by using the bioassay-guided isolation technique from toxic soil of the replanted Chinese fir tree ecosystem. Chemical structures were determined by spectroscopic means, including 2D-NMR (COSY, HMQC, HMBC, and NOESY) experiments. High concentrations of soil phenolics and friedelin were observed in the natural evergreen broadleaf forest (CK) rather than in the Chinese fir tree ecosystem. The phenolics and friedelin were not phytotoxic to Chinese fir trees. However, the cyclic dipeptide inhibited Chinese fir growth at soil concentrations determined in the replanted Chinese fir tree ecosystem. There was a significantly higher soil concentration of cyclic dipeptide in the replanted Chinese fir tree ecosystem than in a fresh Chinese fir tree ecosystem. The results suggest that phenolics and friedelin are not key allelochemicals since they are weakly phytotoxic and are detected in low concentrations in the replanted Chinese fir tree ecosystem, while cyclic dipeptide is a highly active allelochemical with a phytotoxic effect that limits offspring growth in the replanted Chinese fir tree ecosystem. The discovery of cyclic dipeptide, as well as a further understanding of its potential action mechanism in the replanted Chinese fir tree ecosystem, may contribute to solving the replant problems in managed tree ecosystems.

Growth and development of silver fir (Abies alba Mill.) regeneration and restoration of the species in the Karkonosze Mountains

The main task of the study was to investigate the growth conditions of silver fir natural regeneration in the Karkonosze Mts. (Poland). The paper examines the quantity and quality of light reaching the forest floor in stands of different canopies. The aim of the study was also to define the optimal site conditions for silver fir planting under stand canopy. Data on the natural regeneration and stand structure of each investigated stand were collected on circular plots in a grid of 15 × 15 m in 1999 and 2000. Biometric measurements of fir plants planted under various stand canopies were done three times (May 1999, autumn 2000 and 2001). It was found that the fir was not a dominant tree in all size classes from seedlings to saplings. Seedlings (both phases) of spruce, beech, sycamore and rowan occurred in all studied stands. The optimal conditions for fir development were found under larch canopy. That was demonstrated by the highest increment of height, diameter and offshoots. The worst conditions for fir growth were under beech and spruce canopy, which was indicated by the lowest diameter and height. The highest PAR was recorded under pine canopy, whereas the lowest one under beech canopy. Beech stand induced a lower R:FR ratio than the other tree species both on sunny and cloudy days. The highest R:FR ratio was found under the canopy of larch and pine stands.

Differences in Spruce Budworm Defoliation among Balsam Fir and White, Red, and Black Spruce

Abstract Spruce budworm (Choristoneura fumiferana Clem.) outbreaks severely reduce growth and survival of balsam fir (Abies balsamea [L.] Mill.) and spruce (Picea spp. A. Dietr.) over much of eastern North America, resulting in major reductions in yield and disruption of harvest schedules. This is the first study to rigorously quantify defoliation differences among all four spruce budworm host tree species at a stand level. An extensive permanent sample plot data set, with more than 27,000 tree and 1,117 stand measurements from 1984 to 1992 in New Brunswick, Canada, revealed a clear and consistent hierarchy of host species defoliation susceptibility. Regardless of defoliation severity and other stand variables tested, white (Picea glauca [Moench] Voss), red (Picea rubens Sarg.), and black spruce (Picea mariana [Mill.] B.S.P.) had approximately 72, 41, and 28% as much defoliation as balsam fir, respectively. Balsam fir defoliation was a highly significant predictor of white, red, and black spruce defoliation. Of the variation in defoliation of red-black spruce hybrids, 34% was explained by balsam fir defoliation and an interaction with spruce hybrid index. This is the first model to quantify hybrid red-black spruce defoliation across a full range of severities. Quantitative models of stand-level defoliation differences among host species will improve spruce budworm stand impact forecasts and decision support prioritization of bioinsecticide or salvage operations and provide information to calibrate population-defoliation models for host species in mixed species stand types.

Crescita radiale e risposte climatiche dell’abete bianco (Abies alba Mill.) in Basilicata

A dendroclimatic study on silver fir (Abies alba Mill.) was carried out in the Abetina of Ruoti (PZ, Basilicata - southern Italy), a nearly natural mixed Quercus cerris - Silver fir forest. Observations were made on twenty-three large size dominant silver fir trees and dendroecological analyses performed for the period 1866-2007. Results show that late spring/summer precipitations, rather than temperatures, are the most critical factor affecting silver fir growth in this area.

Long-term outcome of precommercial thinning in northwestern New Brunswick: growth and yield of balsam fir and red spruce

A study was established between 1959 and 1961 to study the long-term responses of balsam fir ( Abies balsamea (L.) Mill.) and red spruce ( Picea rubens Sarg.) to precommercial thinning. Three nominal spacings of 4 ft (1.2 m), 6 ft (1.8 m), and 8 ft (2.4 m) were compared with an unthinned control in a randomized complete block design with five replicates. At the time of thinning, natural regeneration averaged 16 years of age, 8 years after harvest. Although thinning had minimal effect on gross total volume production over a 42 to 44 year observation period, actual spacings between 2.1 and 2.5 m produced an average of 360 m3·ha–1gross merchantable volume (GMV), representing a 21% gain over unthinned stands. The same spacings produced quadratic mean diameters of 21 and 23 cm, respectively, compared with 18 cm in the unthinned stands. These size increases translated to individual stem volume gains of 33% and 62%, significantly reducing the age at which thinned stands would meet a specified minimum requirement for merchantability or habitat. The mean annual increment of GMV ranged from 6 m3·ha–1·year–1in unthinned stands, to more than 7 m3·ha·–1·year–1in the thinned stands, and had not yet culminated an average of 50 years postharvest.

Field Note: Alternative Leader Growth Control for Fraser Fir and Korean Fir Christmas Trees

Abstract Excessive leader growth is a challenge for Christmas tree growers who are seeking about 30–35 cm (12–14 in.) shoot elongation for good balance between height and lateral growth. Current cultivation practices include manually pruning leaders to 30–35 cm. In this studywe investigated the use of a growth regulator Ethyl-naphthaleneacetate acid (NAA) and a girdling process using a five-bladed plier (Top-Stop Nipper, Monterey Lawn and Gardens Products, Inc., Fresno, CA) as alternative methods to slow leader growth in Fraser fir (Abies fraseri [Pursh]Poir.), and Korean fir (Abies koreana Wils). NAA applications at rates of 40–160 ml/L reduced the height growth in both Fraser fir and Korean fir. However, in Fraser fir, other morphological parameters such as the leader straightness and bud density were generally adversely affected.The highest rates of 250 and 500 ml/l caused unacceptable reduction in growth and in many cases leader death. NAA applications on Korean fir resulted in significant reduction of leader growth and significantly increased the bud density without negative impact on leader straightness. Partialgirdling of stems was not effective at reducing the leader height in both Fraser fir and Korean fir.