scholarly journals Twenty-Five-Year Growth and Mortality of Planted Ponderosa Pine Repeatedly Thinned to Different Stand Densities in Northern California

1997 ◽  
Vol 12 (4) ◽  
pp. 122-130 ◽  
Author(s):  
William W. Oliver

Abstract A 20 yr old ponderosa pine (Pinus ponderosa var. ponderosa) plantation on a productive site on the west slope of the Sierra Nevada in northern California was thinned four times over a 25 yr period. Stand densities tested were Stand Density Indexes (SDI) of 73, 128, 183, 238, and 293 (equivalent to 40,70,100,130, and 160 ft2/ac of basal area), replicated three times in a randomized design. Growth was analyzed for each of five 5 yr periods. Periodic annual increments (PAI) of diameter, net basal area, and net total volume differed significantly among periods and, in the earlier periods, among stocking levels. Mortality from winter storms and bark beetles was largely confined to the higher stand densities and in periods 3 and 4 caused PAIs of net basal area and net total volume to decline below that of lower densities. The sensitivity of mortality to stand density suggests a thinning target of SDI 183 (about 100 ft²/ac of basal area) for similar stands—no higher than that recommended for eastside stands of much lower site productivity. This sensitivity coupled with rapid growth suggests that multiple thinnings will be necessary in similar stands to maintain healthy, vigorous trees. West. J. Appl. For. 12(4):122-130.

2013 ◽  
Vol 43 (4) ◽  
pp. 311-320 ◽  
Author(s):  
Jianwei Zhang ◽  
Martin W. Ritchie ◽  
Douglas A. Maguire ◽  
William W. Oliver

We analyzed 45 years of data collected from three ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) levels-of-growing-stock installations in Oregon (OR) and northern California (CA), USA, to determine the effect of stand density regimes on stand productivity and mortality. We found that periodic annual increment (PAI) of diameter, basal area (BA), volume, and aboveground dry mass were significantly related to stand density index (SDI) and stand age at start of the period; the quadratic trends varied among sites. Precipitation departure from the normal for each period explained a significant amount of residual variation in all PAI variables except diameter. BA production did not change significantly as SDI exceeded 270 trees·ha−1 at the OR sites and 320 trees·ha−1 at the CA site. Stand productivity was the highest at Elliot Ranch (CA) and the least at Blue Mountains (OR). A similar trend held in growth efficiency under lower stand densities (SDI < 600). Most of the mortality was caused by Dendroctonus bark beetles in stands that exceeded SDI of 500 trees·ha−1. Limiting SDI was about 900 trees·ha−1, although plots at Elliot Ranch reached much higher than that. The results demonstrate that silvicultural control of stand density can be a powerful tool for reducing bark beetle caused mortality without sacrificing stand productivity.


1995 ◽  
Vol 10 (3) ◽  
pp. 91-94
Author(s):  
Darrell W. Ross

Abstract Second-growth ponderosa pine (Pinus ponderosa) stands with outbreak populations of the pandora moth (Coloradia pandora) were thinned from below removing about half of the basal area. Thinning had no effect on pandora moth pupal density or weight, or emerging adult density in the following generation. However, adult emergence and egg hatch occurred 7-10 days earlier in thinned plots compared with unthinned plots. Egg and larval densities on a foliage weight basis were not significantly different between thinned and unthinned plots. Thinning stands infested with pandora moth will not significantly affect the course of an outbreak for at least one generation. Timing of direct controls for the pandora moth should consider the effect of stand density on insect phenology. West. J. Appl. For. 10(3):91-94.


2008 ◽  
Vol 23 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Shawn Kenaley ◽  
Robert Mathiasen ◽  
E. James Harner

Abstract Ponderosa pine (Pinus ponderosa Douglas ex C. Lawson var. scopulorum Engelm.) mortality was evaluated from a 2002 bark beetle outbreak in areas infested with southwestern dwarf mistletoe (Arceuthobium vaginatum [Willd.] Presl subsp. cryptopodum [Engelm.] Hawksw. & Wiens) in a total of nine study sites in northern Arizona. Ponderosa pine mortality attributable to bark beetles (Ips and Dendroctonus spp., Scolytidae) was systematically sampled, and stand attributes, such as basal area, tree density, dwarf mistletoe severity, and site indices were recorded. Ponderosa pine mortality was predominately attributed to Ips spp. Although the prolonged drought likely was the inciting factor responsible for the Ips spp. outbreak, results suggested a strong relationship between ponderosa pine mortality and the interaction between crown class and dwarf mistletoe rating class. Ponderosa pines severely infected with dwarf mistletoe and in the intermediate crown class are at the greatest risk of Ips spp. attack during outbreak years in northern Arizona.


2008 ◽  
Vol 38 (5) ◽  
pp. 909-918 ◽  
Author(s):  
Jianwei Zhang ◽  
Martin W. Ritchie ◽  
William W. Oliver

A large-scale interior ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.) study was conducted at the Blacks Mountain Experimental Forest in northeastern California. The primary purpose of the study was to determine the influence of structural diversity on the dynamics of interior pine forests at the landscape scale. High structural diversity (HiD) and low structural diversity (LoD) treatments were created with mechanical thinning on 12 main plots. Each plot was then split in half with one-half treated with prescribed fire. During the 5 year period after the treatments, the LoD treatments showed slightly higher periodic annual increments for basal area (BA) and significantly higher diameter increments than did the HiD treatments, although HiD carried twice as much BA as LoD did immediately after the treatments. Prescribed fire did not affect growth, but killed and (or) weakened some trees. No interaction between treatments was found for any variable. Stand density was reduced from the stands before treatments, but species composition did not change. Old dominant trees still grew and large snags were stable during the 5 year period. Treatments had minor impacts on shrub cover and numbers. These results suggest that ponderosa pine forest can be silviculturally treated to improve stand growth and health without sacrificing understory shrub diversity.


2011 ◽  
Vol 41 (5) ◽  
pp. 1031-1046 ◽  
Author(s):  
Chris J.K. MacQuarrie ◽  
Barry J. Cooke

Thinning, the selective removal of some trees from a forest, is one way forest managers can reduce the probability that a forest will be susceptible to attack by bark beetles. Although this method has been shown to be effective, it is not clear whether the effect arises when pre-outbreak populations are small or during the epidemic phase when outbreaks are growing. We adopted a population dynamics approach to determine if the effect of limit or basal area thinning could be observed in the form of differential beetle recruitment using lodgepole pine ( Pinus contorta Dougl. ex Loud.) and ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.) mortality data from previously published studies as a proxy measure of mountain pine beetle ( Dendroctonus ponderosae Hopkins) population size. We found that mountain pine beetle populations exhibit density-dependent population dynamics that are influenced by the silvicultural history of their host’s stand. Thinning did not change the epidemic equilibrium but instead caused a shift in dynamics from linear to nonlinear. In a validation test, the models developed for thinned and unthinned stands predicted reproductive rates in independent locations. These data also suggest the epidemic dynamics of mountain pine beetle may be sensitive to perturbations and to systematic trends associated with climate variability and climate change.


1993 ◽  
Vol 8 (4) ◽  
pp. 126-132 ◽  
Author(s):  
P. H. Cochran ◽  
James W. Barrett

Abstract A spacing study in ponderosa pine (Pinus ponderosa) was established in 1959 by thinning plots in a 33-yr-old plantation near John Day, Oregon. The influence of 4 spacings (17.2, 12.5, 10.1, and 8.7 ft) on stand and tree growth for a 31-yr period was examined. Study plots were remeasured five times after establishment. Periodic annual increments (PAI) of gross basal area, gross volume, and average height differed with period but not with spacing (P ≤ 0.10). The PAIs of mean diameter differed with period and decreased with increasing density. Annual height growth and annual gross and net growth of basal area and volume did not differ with spacing. Annual diameter growth was much greater for trees at the widest spacing. Annual volume growth of the largest 90 trees/ac was greatest at the widest spacing. Thirty-one years after thinning, the largest 90 trees/ac on the widest spacing had 73% of the volume of all the trees on the narrowest spacing. Mortality due to mountain pine beetle (Dendroctonus ponderosae) increased markedly when values for stand density index exceeded 200. Wide spacings increased average tree volumes, increased mean diameters, and reduced the probability of mortality without sacrificing gross cubic volume growth potential. West. J. Appl. For. 8(4):126-132.


2016 ◽  
Vol 46 (1) ◽  
pp. 101-113 ◽  
Author(s):  
Kathryn I. McGown ◽  
Kevin L. O’Hara ◽  
Andrew Youngblood

We used six metrics of size and growth variation (standard deviation (SD), coefficient of variation (CV), skewness coefficient (S), Gini coefficient (G), Lorenz asymmetry coefficient (LAC), and growth dominance coefficient (GD)) to describe changes in two long-term ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) initial spacing trials in Oregon and Washington, USA. Trends were examined over a 35-year time period and across a range of initial stand densities (from 154 to 2470 trees·ha−1) for four measures of tree size: diameter at breast height (dbh, 1.37 m), basal area (BA), height, and volume. Unlike many previous studies of size variation in monospecific stands, our results suggest that variation declined or remained relatively stable for all treatments at both study areas. This suggests that these stands are experiencing size symmetric competition for belowground resources. We found that a combination of metrics is necessary to provide a complete picture of size variability and differentiation in developing stands. We recommend using the CV or G, as there were clear trends with increasing density for all size variables. If the objective of the assessment was to track changes in absolute size within an individual stand, we would recommend using the SD, as there were consistent trends with time for all size variables. S, LAC, and GD may be less suited for comparing differentiation during the early stages of stand development because of a lack of clear trends with stand density and time.


1980 ◽  
Vol 112 (7) ◽  
pp. 725-730 ◽  
Author(s):  
D. J. Goheen ◽  
F. W. Cobb

AbstractThe relationship between bark beetle infestation of ponderosa pine and severity of infection by Ceratocystis wageneri was investigated by closely monitoring 256 trees (136 apparently healthy, 60 moderately diseased, and 60 severely diseased at initiation of study) for beetle infestation from summer 1972 to fall 1975. Disease ratings were updated by periodic examination, and some trees changed disease category during the study. Ninety trees were infested by Dendroctonus brevicomis, D. ponderosae, or both, five by buprestids alone, and one tree died from effects of the pathogen alone. Sixty-two of the beetle-infested trees were severely diseased at time of infestation, 25 were moderately diseased, and only three were apparently healthy. Thus, the results showed that bark beetles were much more likely to infest infected than healthy trees. Among diseased trees, those with advanced infections were most likely to be infested. There was evidence that buprestids (especially Melanophila spp.) and possibly Ips spp. attacked diseased trees prior to Dendroctonus spp. infestation.


Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Robert A. York ◽  
Jacob Levine ◽  
Kane Russell ◽  
Joseph Restaino

Abstract Background Young, planted forests are particularly vulnerable to wildfire. High severity effects in planted forests translate to the loss of previous reforestation investments and the loss of future ecosystem service gains. We conducted prescribed burns in three ~35-year-old mixed conifer plantations that had previously been masticated and thinned during February in order to demonstrate the effectiveness of winter burning, which is not common in the Sierra Nevada, California. Results On average, 59% of fine fuels were consumed and the fires reduced shrub cover by 94%. The average percent of crown volume that was damaged was 25%, with no mortality observed in overstory trees 1 year following the fires. A plot level analysis of the factors of fire effects did not find strong predictors of fuel consumption. Shrub cover was reduced dramatically, regardless of the specific structure that existed in plots. We found a positive relationship between crown damage and the two variables of Pinus ponderosa relative basal area and shrub cover. But these were not particularly strong predictors. An analysis of the weather conditions that have occurred at this site over the past 20 years indicated that there have consistently been opportunities to conduct winter burns. On average, 12 days per winter were feasible for burning using our criteria. Windows of time are short, typically 1 or 2 days, and may occur at any time during the winter season. Conclusions This study demonstrates that winter burning can be an important piece of broader strategies to reduce wildfire severity in the Sierra Nevada. Preparing forest structures so that they can be more feasible to burn and also preparing burn programs so that they can be nimble enough to burn opportunistically during short windows are key strategies. Both small landowners and large agencies may be able to explore winter burning opportunities to reduce wildfire severity.


1994 ◽  
Vol 9 (2) ◽  
pp. 57-61 ◽  
Author(s):  
Philip M. McDonald ◽  
Gary O. Fiddler ◽  
Jay H. Kitzmiller

Abstract Three classes of ponderosa pine (Pinus ponderosa) seedlings (nursery-run, wind-pollinated, control-pollinated) were evaluated for stem height and diameter at the USDA Forest Service's Placerville Nursery and the Georgetown Ranger District in northern California. Pines in all three classes were grown with competing vegetation or maintained in a free-to-grow condition. Control-pollinated seedlings were statistically taller (P < 0.05) than nursery-run counterparts when outplanted, and after 1 and 2 growing seasons in the field with and without competition. They also had significantly larger diameters when outplanted and after 2 growing seasons in the field when free to grow. Wind-pollinated seedlings grew taller than nursery-run seedlings when free to grow. A large amount of competing vegetation [bearclover (Chamaebatia foliolosa)—29,490 plants per acre; herbaceous vegetation—11,500; hardwood sprouts—233; and whiteleaf manzanita (Arctostaphylos viscida) seedlings—100] ensure that future pine development will be tested rigorously. West. J. Appl. For. 9(2):00-00.


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