Structure and yield of two-aged stands on the Willamette National Forest, Oregon: implications for green tree retention

1998 ◽  
Vol 28 (5) ◽  
pp. 749-758 ◽  
Author(s):  
S A Acker ◽  
E K Zenner ◽  
W H Emmingham
Keyword(s):  
Basal Area ◽  
Average Diameter ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
National Forest ◽  
Annual Increment ◽  
Ecosystem Science ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Residual Tree

Green tree retention, a practice based on ecosystem science, has been integrated into forest management as a working hypothesis, requiring research and monitoring to quantify its effects. We undertook a retrospective study of natural, two-aged forest stands on the Willamette National Forest to provide preliminary estimates of the effects of green tree retention on forest structure and yield. Fourteen stands in the western hemlock (Tsuga heterophylla (Raf.) Sarg.) zone (mostly dominated by Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco) were sampled using adjacent, paired plots: one with residual trees over a younger cohort (median age of younger cohort, 97 years) and one with only the younger cohort. The younger cohorts all had much higher densities of trees than typical of local Douglas-fir plantations. Basal area, volume, and mean annual increment (MAI) of the younger cohort all declined with increasing residual tree basal area. These relationships were best described by curvilinear models; the greatest effect per unit of residual tree basal area occurred at low residual tree levels (5-10 m2/ha). For 10 m2/ha residual tree basal area (equivalent to about 12 average (diameter at breast height 105 cm) residual trees per hectare), we predicted a 26% decline in younger cohort MAI (95% confidence interval: -30% to -22%).

scholarly journals Effects of Varying Levels and Patterns of Green-Tree Retention on Amount of Harvesting Damage

2002 ◽  
Vol 17 (4) ◽  
pp. 202-206 ◽  
Author(s):  
John R. Moore ◽  
Douglas A. Maguire ◽  
David L. Phillips ◽  
Charles B. Halpern
Keyword(s):  
Pseudotsuga Menziesii ◽  
Tsuga Heterophylla ◽  
Growth Reduction ◽  
Management Options ◽  
Treatment Implementation ◽  
Dispersed Retention ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Aggregated Retention ◽  
Future Growth

Abstract An inventory of fresh logging wounds from treatment implementation was performed in a regional green-tree retention experiment in Oregon and Washington. The DEMO (Demonstration of Ecosystem Management Options) study contains six treatments replicated in six blocks: (1) 100% retention (control), (2) 75% aggregated retention, (3) 40% dispersed retention, (4) 40% aggregated retention, (5) 15% dispersed retention, and (6) 15% aggregated retention. Over all blocks and treatments, Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) comprised 74.9% of all measured trees, and the proportion of trees damaged was similar for both species. Suppressed trees tended to be more susceptible to damage than were trees in other crown classes. A greater proportion of trees in the dispersed retention treatments were damaged than in the aggregated treatments. Only in the two dispersed retention treatments were levels of damage significantly different from the control (P < 0.05). The greatest proportion of damaged trees occurred in the 15% dispersed retention treatment and was likely due to the wider dispersion and higher intensity of felling and yarding operations associated with this treatment. The pattern of damage across treatments was similar for both small (≤ 25 cm dbh) and large (> 25 cm dbh) trees. Some evidence was also found that the sites with gentler slopes had less damage than those with steeper topography. Probable effects of wounds on future growth and tree health could not be inferred as no data were collected on wound size or height. However, it is expected that the future incidence of stem rot and growth reduction will be greatest in the dispersed retention treatments. West. J. Appl. For. 17(4):202–206.

SEASONAL VARIATIONS IN RADIAL GROWTH AT BREAST HEIGHT OF SOME WESTERN HEMLOCK AND DOUGLAS FIR TREES, 1953-57

1960 ◽  
Vol 36 (4) ◽  
pp. 391-400 ◽  
Author(s):  
Braham G. Griffith
Keyword(s):  
Average Length ◽  
Basal Area ◽  
Growing Season ◽  
Average Diameter ◽  
Frost Damage ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Radial Increment ◽  
Breast Height ◽  
Total Growth

Radial increment was recorded at weekly intervals for 68 Douglas fir and 14 western hemlock trees throughout the growing season for the years 1953-57 inclusive. The average diameter, inside bark at breast height, was 13.9 inches for the Douglas firs and 11.9 inches for the western hemlock. Growth for both species generally commenced during the first week of May. The average length of the growing season for Douglas fir was 146 days and for western hemlock 156 days. Douglas fir completed a greater percentage of its total growth earlier in the season than did western hemlock, accounting for an average of 83 per cent of its basal area growth by July 31 compared to 68 per cent for western hemlock. Growth in both 1956 and 1957 was considerably below that of each of the preceding three years. This was attributed partly to the severe frost damage to the trees in November 1955.

scholarly journals Growth assessment of upper hill dipterocarp (Shorea platyclados) at the various slope in a rehabilitated landscape

2021 ◽  
Vol 914 (1) ◽  
pp. 012027
Author(s):  
F Reksawinata ◽  
P Pamoengkas ◽  
H H Rachmat
Keyword(s):  
Growth Performance ◽  
Basal Area ◽  
Tree Height ◽  
Average Diameter ◽  
Stem Diameter ◽  
Average Height ◽  
Annual Increment ◽  
Area Index ◽  
Shorea Platyclados ◽  
Mean Annual Increment

Abstract Rehabilitation aims to improve landscape function while increasing its resilience to climate change. Gunung Dahu research forest is a rehabilitated hilly landscape that is planted with more than 25 dipterocarp species, including an upper hill dipterocarp tree of Shorea platyclados at various site conditions. This study aimed to assess the growth performance of S. platyclados at five sloping levels class of 0-8%, 8-15%, 15-25%, 25-45%, and >45%. Observed growth attributes were stem diameter, total height, basal area, Mean Annual Increment (MAI), and Leaf Area Index (LAI), and diameter. The results showed that sloping levels significantly affect the growth performance of the planted trees. The highest slope level (>45%) supported the highest average stem diameter and tree height (41.48 cm and 20.86 m). The sloping level of >45%, 25-45%, 15-25%, 8-15%, and 0-8% yield different value of average diameter which were 41.48 cm, 35.86 cm, 36.54 cm, 34.61 cm, and 31.23, while the average height were 20, 86m, 19.78 m, 16.72 m, 18.84 m, 18.61 m respectively. Thus, the upper hill dipterocarp of S. platyclados is a prospective native tree species for rehabilitating hilly upland landscapes.

Green-tree retention and recovery of an old-forest specialist, the southern red-backed vole (Myodes gapperi), 20 years after harvest

2017 ◽  
Vol 44 (8) ◽  
pp. 669 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Druscilla S. Sullivan
Keyword(s):  
Small Mammals ◽  
Pinus Contorta ◽  
Mammalian Species ◽  
Basal Area ◽  
Structural Diversity ◽  
Post Harvest ◽  
Forest Sites ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Aggregated Retention

Context Populations of many mammalian species are reduced as a result of clearcutting, despite the concurrent objectives of wood production and conservation of mammal diversity on cutover forest land. To help ameliorate this decline, green-tree retention (GTR) leaves large live trees after harvest to provide mature forest habitat and increase structural diversity of the regenerating stand. Aims To test the hypotheses (H) that, at 20 years after harvest, (H1) abundance, reproduction and survival of the southern red-backed vole (Myodes gapperi), as well as (H2) abundance and species diversity of the forest-floor small mammal community, would increase with the basal area (BA) and density of residual trees after harvest. Methods Small mammals were live-trapped in 2015–16 in replicated clearcut, dispersed retention, aggregated retention, patch cut and uncut forest sites in mixed forests of Douglas fir (Pseudotsuga menziesii var. glauca) and lodgepole pine (Pinus contorta Dougl. var. latifolia) in southern British Columbia, Canada. Key results Mean BA and density of overstory coniferous trees were significantly different at 20 years post-harvest, being higher on patch cut and uncut forest sites than on the clearcut and GTR sites. M. gapperi populations were significantly greater in aggregated retention and uncut forest sites than in the other sites, but demographic parameters were similar among sites, and therefore H1 was partly supported. Mean total abundance of small mammals differed significantly among sites, with the highest overall numbers occurring in the aggregated retention (16.2), clearcut (13.6) and uncut forest sites (11.9). Mean species richness and diversity were highest in the GTR and clearcut sites. Thus, H2 was not supported. Conclusions Recovery of M. gapperi in aggregated retention sites with 10m2 ha–1 BA of residual trees, as a group, occurred at 20 years post-harvest. Implications Aggregated retention of residual trees should help provide some habitat to conserve forest mammals on harvest openings, but successional development up to 20 years post-harvest may be required.

Prediction of Douglas-fir fertilizer response using biogeoclimatic properties in the coastal Pacific Northwest

2014 ◽  
Vol 44 (10) ◽  
pp. 1253-1264 ◽  
Author(s):  
K.M. Littke ◽  
R.B. Harrison ◽  
D. Zabowski ◽  
M.A. Ciol ◽  
D.G. Briggs
Keyword(s):  
Pacific Northwest ◽  
Pearson Correlation ◽  
Regression Tree ◽  
Correlation Coefficients ◽  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Annual Increment ◽  
Fertilizer Response ◽  
Boosted Regression Tree

Fertilizer response of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) has been related to site and soil properties in the past, but the models have explained only about half of the variation in these investigations. Fertilizer response and percent response after two years were examined, according to mapped and measured biogeoclimatic variables, for 71 Douglas-fir installations in the coastal Pacific Northwest. Paired-tree installations consisted of 12–20 pairs of Douglas-fir trees with one tree fertilized with urea at 224 kg N·ha−1. Pearson correlation coefficients and boosted regression tree (BRT) models were used to determine the best predictor variables and models of Douglas-fir fertilizer response. The BRT models, using the combination of mapped and measured variables, performed the best for predicting fertilizer response. Basal area and volume responses were most related to high forest floor and surface soil carbon to nitrogen ratios. Basal area mean annual increment (MAI) and site index were both negatively correlated with fertilizer response. Also, low basal area MAI was the most important tree measurement for predicting fertilizer response in the BRT models. Installations with many of the predictors from the BRT models (>66% of the model criteria) were found to have a significantly greater fertilizer response than installations with only a few predictors (<33% of the model criteria). These findings support the use of these models for predicting fertilizer response of similar Douglas-fir stands in the coastal Pacific Northwest.

CFIRP: What we learned in the first ten years

1999 ◽  
Vol 75 (3) ◽  
pp. 431-434 ◽  
Author(s):  
Carol L. Chambers ◽  
William C. McComb ◽  
John C. Tappeiner II ◽  
Loren D. Kellogg ◽  
Rebecca L. Johnson ◽  
...  
Keyword(s):  
Pseudotsuga Menziesii ◽  
Group Selection ◽  
Structural Features ◽  
Human Dimensions ◽  
Douglas Fir ◽  
Small Scale ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Patch Group

In response to public dissatisfaction with forest management methods, we initiated the College of Forestry Integrated Research Project (CFIRP) to test alternative silvicultural systems in Douglas-fir (Pseudotsuga menziesii) stands in western Oregon. We compared costs and biological and human responses among a control and three replicated silvicultural alternatives to clearcutting that retained structural features found in old Douglas-fir forests. Treatments were applied within 8- to 15-ha stands and attempted to mimic crown fires (modified clearcut), windthrow (green tree retention), and small-scale impacts such as root rot diseases (small patch group selection). We also compared costs in three unreplicated treatments (large patch group selection, wedge cut, and strip cut). Each treatment included differences in the pattern of retained dead trees (snags), as either scattered individuals or as clumps. Good communication among researchers and managers, a long-term commitment to the project, and careful documentation of research sites and data are important to the success of long-term silvicultural research projects. To date, over 30 publications have resulted from the project. Key words: alternative silviculture, data management, Douglas-fir, green tree retention, harvesting costs, human dimensions, Oregon, Pseudotsuga menziesii, recreation, wildlife

Contribution to the automation of the calculations involving the forest inventory with the aid of an office computer

1970 ◽  
Vol 20 ◽  
Author(s):  
R. Goossens
Keyword(s):  
Tree Species ◽  
Forest Inventory ◽  
Basal Area ◽  
Annual Increment ◽  
Mixed Stands ◽  
Mean Values ◽  
Standing Trees ◽  
General Program ◽  
Magnetic Card ◽  
The Right

Contribution to the automation of the calculations involving  the forest inventory with the aid of an office computer - In this contribution an attempt was made to perform the  calculations involving the forest inventory by means of an office computer  Olivetti P203.     The general program (flowchart 1), identical for all tree species except  for the values of the different parameters, occupies the tracks A and B of a  magnetic card used with this computer. For each tree species one magnetic  card is required, while some supplementary cards are used for the  subroutines. The first subroutine (flowchart 1) enables us to preserve  temporarily the subtotals between two tree species (mixed stands) and so  called special or stand cards (SC). After the last tree species the totals  per ha are calculated and printed on the former, the average trees occuring  on the line below. Appendix 1 gives an example of a similar form resulting  from calculations involving a sampling in a mixed stand consisting of Oak  (code 11), Red oak (code 12), Japanese larch (code 24) and Beech (code 13).  On this form we find from the left to the right: the diameter class (m), the  number of trees per ha, the basal area (m2/ha), the current annual increment  of the basal area (m2/year/ha), current annual volume increment (m3/year/ha),  the volume (m3/ha) and the money value of the standing trees (Bfr/ha). On the  line before the last, the totals of the quantities mentioned above and of all  the tree species together are to be found. The last line gives a survey of  the average values dg, g, ig, ig, v and w.     Besides this form each stand or plot has a so-called 'stand card SC' on  wich the totals cited above as well as the area of the stand or the plot and  its code are stored. Similar 'stand card' may replace in many cases  completely the classical index cards; moreover they have the advantage that  the data can be entered directly into the computer so that further  calculations, classifications or tabling can be carried out by means of an  appropriate program or subroutine. The subroutine 2 (flowchart 2) illustrates  the use of similar cards for a series of stands or eventually a complete  forest, the real values of the different quantities above are calculated and  tabled (taking into account the area). At the same time the general totals  and the general mean values per ha, as well as the average trees are  calculated and printed. Appendix 2 represents a form resulting from such  calculations by means of subroutine 2.

Preliminary DRIS norms for coastal Douglas-fir soils in Washington and Oregon

1995 ◽  
Vol 25 (2) ◽  
pp. 208-214 ◽  
Author(s):  
J.S. Shumway ◽  
H.N. Chappell
Keyword(s):  
Basal Area ◽  
Site Index ◽  
Douglas Fir ◽  
Integrated System ◽  
N Fertilizer ◽  
Soil Test ◽  
Fertilizer Response ◽  
Response Data ◽  
Limiting Nutrient ◽  
Diagnostic Work

The Diagnosis and Recommendation Integrated System (DRIS) has been used successfully in agricultural crops and holds promise for use in forest stands. This study used soil tests to develop DRIS norms and evaluate their effectiveness in coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forests. DRIS norms for nitrogen, phosphorus, potassium, and calcium were developed using soil test and site index data from 72 soil series that commonly support Douglas-fir in western Washington. The norms were tested using soil test and stand basal area growth response data from 20 thinned and 30 unthinned N fertilizer test sites in coastal Washington and Oregon. Response to urea fertilizer in thinned stands averaged 34% and 43% for 224 and 448 kg N•ha−1, respectively, when N was identified as the most limiting nutrient. When N was not the most limiting nutrient, N response averaged 8% and 10% for 224 and 448 kg N•ha−1, respectively. Results were similar in unthinned stands and thinned stands, although response to fertilizer appeared to be slightly less in unthinned stands when N was the most limiting nutrient. DRIS correctly classified 25 of the 33 sites (76%) where N fertilizer increased growth by more than 15%. More importantly, 13 of the 17 (76%) sites that responded by less than 15% were correctly identified by DRIS. The results clearly indicate that N fertilizer response is dependent on the interactions (balance) between soil nutrients at a given site. Future soil diagnostic work needs to focus on techniques, like DRIS, that provide an assessment of these interactions.

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