Canopy characteristics and growth rates of ponderosa pine and Douglas-fir at long-established forest edges

2007 ◽  
Vol 37 (11) ◽  
pp. 2096-2105 ◽  
Author(s):  
Kelsey Sherich ◽  
Amy Pocewicz ◽  
Penelope Morgan

Trees respond to edge-to-interior microclimate differences in fragmented forests. To better understand tree physiological responses to fragmentation, we measured ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws) and Douglas-fir ( Pseudotsuga menziesii (Mirbel) Franco) leaf area, crown ratios, sapwood area, basal area (BA) growth rates, and BA growth efficiency at 23 long-established (>50 year) forest edges in northern Idaho. Trees located at forest edges had more leaf area, deeper crowns, higher BA growth rates, and more sapwood area at breast height than interior trees. Ponderosa pine had significantly higher BA growth efficiency at forest edges than interiors, but Douglas-fir BA growth efficiency did not differ, which may relate to differences in photosynthetic capacity and drought and shade tolerance. Edge orientation affected BA growth efficiency, with higher values at northeast-facing edges for both species. Edge effects were significant even after accounting for variation in stand density, which did not differ between the forest edge and interior. Although edge trees had significantly greater canopy depth on their edge-facing than forest-facing side, sapwood area was evenly distributed. We found no evidence that growing conditions at the forest edge were currently subjecting trees to stress, but higher leaf area and deeper crowns could result in lower tolerance to future drought conditions.

2007 ◽  
Vol 37 (2) ◽  
pp. 343-355 ◽  
Author(s):  
Nate G. McDowell ◽  
Henry D. Adams ◽  
John D. Bailey ◽  
Thomas E. Kolb

We examined the response of growth efficiency (GE), leaf area index (LAI), and resin flow (RF) to stand density manipulations in ponderosa pine ( Pinus ponderosa Dougl. ex Laws.) forests of northern Arizona, USA. The study used a 40 year stand density experiment including seven replicated basal area (BA) treatments ranging from 7 to 45 m2·ha–1. Results were extended to the larger region using published and unpublished datasets on ponderosa pine RF. GE was quantified using basal area increment (BAI), stemwood production (NPPs), or volume increment (VI) per leaf area (Al) or sapwood area (As). GE per Al was positively correlated with BA, regardless of numerator (BAI/Al, NPPs/Al, and VI/Al; r2 = 0.84, 0.95, and 0.96, respectively). GE per As exhibited variable responses to BA. Understory LAI increased with decreasing BA; however, total (understory plus overstory) LAI was not correlated with BA, GE, or RF. Opposite of the original research on this subject, resin flow was negatively related to GE per Al because Al/As ratios decline with increasing BA. BAI, and to a lesser degree BA, predicted RF better than growth efficiency, suggesting that the simplest measurement with the fewest assumptions (BAI) is also the best approach for predicting RF.


2004 ◽  
Vol 34 (11) ◽  
pp. 2217-2229 ◽  
Author(s):  
Douglas B Mainwaring ◽  
Douglas A Maguire

Basal area and height growth were analyzed for individual trees in uneven-aged ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and lodgepole pine (Pinus contorta Dougl. ex. Loud.) stands in central Oregon. Basal area growth was modeled as a function of other stand and tree variables to address three general objectives: (1) to compare the predictive ability of distance-dependent versus distance-independent stand density variables; (2) to determine the degree to which small trees negatively affect the growth of overstory trees; and (3) to test for differences in growth efficiency between species and between indices of spatial occupancy used to define efficiency (area potentially available, crown projection area, and a surrogate for total tree leaf area). Distance-dependent variables were found to improve growth predictions when added to models with only distance-independent variables, and small trees were found to have a quantifiably negative effect on the growth of larger trees. While volume growth efficiency declined with increasing levels of spatial occupancy for lodgepole pine, ponderosa pine volume growth efficiency was greatest at the highest levels of crown base sapwood area and crown projection area. The behavior in ponderosa pine resulted from the previously recognized correlation between tree height and total leaf area or crown size. The final statistical models distinguished between the positive effect of relative height and the negative effect of increasing tree size.


2003 ◽  
Vol 33 (9) ◽  
pp. 1719-1726 ◽  
Author(s):  
C W Woodall ◽  
C E Fiedler ◽  
K S Milner

Intertree competition indices and effects were examined in 14 uneven-aged ponderosa pine (Pinus ponderosa var. scopulorum Engelm.) stands in eastern Montana. Location, height, diameter at breast height (DBH), basal area increment, crown ratio, and sapwood area were determined for each tree (DBH >3.8 cm) on one stem-mapped plot (0.2-0.4 ha) in each sample stand. Based on tree locations, various competition indices were derived for each sample tree and correlated with its growth efficiency by diameter class. In addition, trends in individual tree attributes by diameter class and level of surrounding competition were determined. For trees with a DBH <10 cm, growth efficiency was most strongly correlated with the sum of surrounding tree heights within 10.6 m. The index most highly correlated for larger trees was the sum of surrounding basal area within 6.1 m. Regardless of tree size, individual tree growth efficiency, basal area increment, and crown ratio all decreased under increasing levels of competition, with the effect more pronounced in smaller trees. These results suggest that individual trees in uneven-aged stands experience competition from differing sources at varying scales based on their size, with response to competition diminishing as tree size increases.


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.


1987 ◽  
Vol 17 (2) ◽  
pp. 174-180 ◽  
Author(s):  
M. A. Espinosa Bancalari ◽  
D. A. Perry ◽  
John D. Marshall

The relationship between foliage area and sapwood basal area was studied in three adjacent 22-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands that differed in early growth rates. Sapwood width was fairly constant for most of the stem above the stump, but the number of annual rings in the sapwood decreased gradually with height. Sapwood area also decreased with increasing height in the tree, the stands differing significantly only at breast height. The proportion of heartwood from stump to near the base of the crown was significantly higher for the stand of fastest early growth. Ratios of leaf area to sapwood area were significantly higher for that stand and varied in every stem section, the ratio lower at breast height than at the base of the live crown. At the base of the crown, the ratio of leaf area to sapwood area was 1.33 and 1.57 times greater in the fast-growing stand than in the intermediate- and slow-growing stands, respectively. Leaf area was as closely related to dbh as to sapwood area at breast height. Sapwood area at the crown base was more accurate than sapwood area at breast height for predicting leaf area in the fast stand and was equally accurate in the other two stands. Ratios of leaf area to sapwood area correlated positively with sapwood ring width. However, because sapwood ring width also correlated closely with sapwood area, it did not improve predictive equations. The results suggest that the "pipe model" theory must be modified to account for the internal structure of the "pipe" and that caution should be exercised when using published leaf area to sapwood area ratios.


1999 ◽  
Vol 29 (5) ◽  
pp. 521-535 ◽  
Author(s):  
Robert A Monserud ◽  
John D Marshall

Allometric equations predicting individual branch and total crown leaf area, leaf mass, and branch wood mass were developed for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca), ponderosa pine (Pinus ponderosa Dougl. ex Laws.), and western white pine (Pinus monticola Dougl. ex D. Don) on the Priest River Experimental Forest in northern Idaho. Whole crowns were weighed fresh in the field by crown quarter. Two antithetic random branches were sampled from each crown quarter, weighed fresh in the field, and returned to the laboratory for detailed analysis. Nonlinear weighted regression with the general allometric equation was used to estimate all parameters. For the branches, branch diameter and length, foliated length, and position in the crown explain 82-97% of the variation. Specific leaf area (leaf area/mass) differs significantly among species and increases with distance from the tree top. For whole trees, sapwood area at breast height, crown ratio and length, and crown competition factor (CCF) explain 94-99% of the variation. The assumption of linearity and constant ratio between leaf area and sapwood area held rather generally. Differences between two alternative estimators (branch summation vs. crown weighing) of total crown biomass and leaf area were not statistically significant. For stands, stand totals were estimated from the whole-tree equations and stand-inventory data. Generally, these stand estimates were intermediate between coastal forests west of the Cascades and drier forests in the rain shadow of the Rocky Mountain crest.


2015 ◽  
Vol 45 (11) ◽  
pp. 1607-1616 ◽  
Author(s):  
Monica T. Rother ◽  
Thomas T. Veblen ◽  
Luke G. Furman

Climate change may inhibit tree regeneration following disturbances such as wildfire, altering post-disturbance vegetation trajectories. We implemented a field experiment to examine the effects of manipulations of temperature and water on ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings planted in a low-elevation, recently disturbed setting of the Colorado Front Range. We implemented four treatments: warmed only (Wm), watered only (Wt), warmed and watered (WmWt), and control (Co). We found that measures of growth and survival varied significantly by treatment type. Average growth and survival was highest in the Wt plots, followed by the Co, WmWt, and Wm plots, respectively. This general trend was observed for both conifer species, although average growth and survival was generally higher in ponderosa pine than in Douglas-fir. Our findings suggest that warming temperatures and associated drought are likely to inhibit post-disturbance regeneration of ponderosa pine and Douglas-fir in low-elevation forests of the Colorado Front Range and that future vegetation composition and structure may differ notably from historic patterns in some areas. Our findings are relevant to other forested ecosystems in which a warming climate may similarly inhibit regeneration by dominant tree species.


1999 ◽  
Vol 29 (12) ◽  
pp. 1993-1996 ◽  
Author(s):  
Barbara L Gartner ◽  
Jeffrey J Morrell ◽  
Camille M Freitag ◽  
Rachel Spicer

Heartwood durability of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) was studied as a function of vertical and radial position in boles of trees with a wide range of leaf area/sapwood area ratios. Six 34-year-old trees were harvested from each of three plots established 14 years before: very dense, thinned, and thinned and fertilized. Heartwood samples from three radial positions and five heights were incubated with the decay fungus Postia placenta (Fr.) M. Larsen et Lombard. There were no significant differences in wood mass loss (decay resistance) by vertical or radial position. One could expect that trees with high leaf area/sapwood area could have the carbon to produce heartwood that is more resistant to decay than trees with lower leaf area/sapwood area. However, we found no relationship between leaf area above node 20, sapwood area there, or their ratio, and the decay resistance of outer heartwood at that node. These results suggest that, for young Douglas-fir trees, heartwood durability does not vary with position in the bole or with environments that alter the tree's balance of sapwood and leaf area. We suggest that young stands may thus be robust with respect to the effect of silvicultural regimes on heartwood durability.


2003 ◽  
Vol 33 (1) ◽  
pp. 164-170 ◽  
Author(s):  
John D Marshall ◽  
Robert A Monserud

Specific leaf area (SLA), the ratio of projected leaf area to leaf dry mass, is a critical parameter in many forest process models. SLA describes the efficiency with which the leaf captures light relative to the biomass invested in the leaf. It increases from top to bottom of a canopy, but it is unclear why. We sampled stands with low and elevated canopies (young and old stands) to determine whether SLA is related to water potential, as inferred from branch height and length, or shade, as inferred from branch position relative to the rest of the canopy, or both. We studied western white pine (Pinus monticola Dougl. ex D. Don), ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.), and interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca) in northern Idaho. SLA decreased with branch height (P < 0.0001) at rates that varied among species (P < 0.0001). Branch length had no influence on SLA (P = 0.85). We detected no differences with canopy elevation (P = 0.90), but the slopes of lines relating SLA to branch height may have differed between the canopy elevation classes (P = 0.039). The results are consistent with predictions based on the hypothesis that SLA decreases as the gravitational component of water potential falls. The lack of a strong shading effect simplifies the estimation of canopy SLA for process models, requiring only species and branch heights.


1992 ◽  
Vol 22 (9) ◽  
pp. 1278-1289 ◽  
Author(s):  
Alejandro Velazquez-Martinez ◽  
David A. Perry ◽  
Tom E. Bell

The effect of thinning and cultural practices (multinutrient fertilization, pruning) on total aboveground biomass increment and growth efficiency was studied over three consecutive 2-year periods (1981–1987) in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations. Net aboveground biomass increment over the 6-year period averaged 14.5, 7.8, and 5.5 Mg•ha−1•year−1 for the high-, medium-, and low-density plots, respectively. Growth efficiency, after dropping sharply between leaf area indexes of 1 and 6 m2/m2, remained relatively constant up to a leaf area index of 17, the highest measured. Consequently, aboveground biomass increment continued to increase at leaf area indexes well above that at which the Beer–Lambert law predicts maximum light should be absorbed. Foliage analyses indicate that thinning improved nitrogen, potassium, and magnesium nutrition and increased the translocation of potassium from 1-year-old foliage to support new growth. However, fertilization increased foliar nitrogen and phosphorus contents only when coupled with pruning, suggesting that trees favor total leaf area over individual needle nutrition. Indications of potassium and magnesium limitations in this study are supported by other recent studies in Douglas-fir. Further work on the role of multinutrient deficiencies in this species is warranted.


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