Unthinned slow-growing ponderosa pine (Pinus ponderosa) trees contain muted isotopic signals in tree rings as compared to thinned trees

Trees ◽  
2014 ◽  
Vol 28 (4) ◽  
pp. 1035-1051 ◽  
Author(s):  
Julia A. Sohn ◽  
J. Renée Brooks ◽  
Jürgen Bauhus ◽  
Martin Kohler ◽  
Thomas E. Kolb ◽  
...  
1999 ◽  
Vol 14 (3) ◽  
pp. 164-168 ◽  
Author(s):  
Michael J. Pipas ◽  
Gary W. Witmer

Abstract A 2 yr study on the Rogue River and Mt. Hood National Forests in Oregon evaluated physical barriers for protection of Pinus ponderosa seedlings against damage by Thomomys talpoides. Seedlings protected with one of three weights of: (1) plastic mesh tubing (Vexar®) or (2) sandpapertubing (Durite®) were evaluated against control seedlings. On the Rogue River sites, Vexar® seedlings had the highest survival (62.6%), followed by the controls (59.1%), then Durite® seedlings (17.9%). Gophers were the primary cause of death for the Vexar® seedlings, versus desiccation for the Durite® seedlings. On the Mt. Hood sites, heavyweight Vexar® seedlings had the highest survival (35.4%), medium-weight Durite® seedlings the lowest (2.7%). Seedling mortality caused by gophers was highest for controls (70.2%), followed by light-weight (62.2%) and heavy-weight (53.9%) Vexar® treatments. Overall survival was low (Rogue River = 42%, Mt. Hood = 19.8%). Growth was greatest for the control seedlings but only significantly greater than growth of Durite® seedlings on the Rogue River sites. Growth of seedlings was not compromised by the Vexar® tubing. Although neither type of tubing was highly protective, Vexar® tubes performed better than Durite® tubes. West. J. Appl. For. 14(3):164-168.


2003 ◽  
Vol 18 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Steven J. Stein ◽  
Diana N. Kimberling

Abstract Information on the mortality factors affecting naturally seeded conifer seedlings is becoming increasingly important to forest managers for both economic and ecological reasons. Mortality factors affecting ponderosa pine (Pinus ponderosa) seedlings immediately following natural germination and through the following year were monitored in Northern Arizona. The four major mortality factors in temporal order included the failure of roots to establish in the soil (27%), herbivory by lepidopteran larvae (28%), desiccation (30%), and winterkill (10%). These mortality factors were compared among seedlings germinating in three different overstory densities and an experimental water treatment. Seedlings that were experimentally watered experienced greater mortality than natural seedlings due to herbivory (40%), nearly as much mortality due to the failure of roots to establish in the soil (20%), less mortality due to winterkill (5%), and no mortality due to desiccation. The seedling mortality data through time were summarized using survivorship curves and life tables. Our results suggest that managers should consider using prescribed burns to decrease the percentage of seedlings that die from failure of their roots to reach mineral soil and from attack by lepidopteran larvae. West. J. Appl. For. 18(2):109–114.


2008 ◽  
Vol 38 (4) ◽  
pp. 844-850 ◽  
Author(s):  
Gregory Peters ◽  
Anna Sala

Thinning and thinning followed by prescribed fire are common management practices intended to restore historic conditions in low-elevation ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.) forests of the northern Rocky Mountains. While these treatments generally ameliorate the physiology and growth of residual trees, treatment-specific effects on reproductive output are not known. We examined reproductive output of second-growth ponderosa pine in western Montana 9 years after the application of four treatments: thinning, thinning followed by spring prescribed fire, thinning followed by fall prescribed fire, and unthinned control stands. Field and greenhouse observations indicated that reproductive traits vary depending on the specific management treatment. Cone production was significantly higher in trees from all actively managed stands relative to control trees. Trees subjected to prescribed fire produced cones with higher numbers of filled seeds than trees in unburned treatments. Seed mass, percentage germination, and seedling biomass were significantly lower for seeds from trees in spring burn treatments relative to all others and were generally higher in trees from fall burn treatments. We show for the first time that thinning and prescribed-burning treatments can influence reproductive output in ponderosa pine.


2004 ◽  
Vol 52 (6) ◽  
pp. 757 ◽  
Author(s):  
M. B. Dickinson ◽  
J. Jolliff ◽  
A. S. Bova

Hyperbolic temperature exposures (in which the rate of temperature rise increases with time) and an analytical solution to a rate-process model were used to characterise the impairment of respiration in samples containing both phloem (live bark) and vascular-cambium tissue during exposures to temperatures such as those experienced by the vascular cambium in tree stems heated by forest fires. Tissue impairment was characterised for red maple (Acer rubrum), chestnut oak (Quercus prinus), Douglas fir (Pseudotsuga menziesii), and ponderosa pine (Pinus ponderosa) samples. The estimated temperature dependence of the model’s rate parameter (described by the Arrhenius equation) was a function of the temperature regime to which tissues were exposed. Temperatures rising hyperbolically from near ambient (30°C) to 65°C produced rate parameters for the deciduous species that were similar at 60°C to those from the literature, estimated by using fixed temperature exposures. In contrast, samples from all species showed low rates of impairment, conifer samples more so than deciduous, after exposure to regimes in which temperatures rose hyperbolically between 50 and 60°C. A hypersensitive response could explain an early lag in tissue-impairment rates that apparently caused the differences among heating regimes. A simulation based on stem vascular-cambium temperature regimes measured during fires shows how temperature-dependent impairment rates can be used to predict tissue necrosis in fires. To our knowledge, hyperbolic temperature exposures have not been used to characterise plant tissue thermal tolerance and, given certain caveats, could provide more realistic data more efficiently than fixed-temperature exposures.


2003 ◽  
Vol 33 (5) ◽  
pp. 870-884 ◽  
Author(s):  
Rick G Kelsey ◽  
Gladwin Joseph

Sixteen days after a September wildfire, ethanol and water were measured in phloem and sapwood at breast height and the base of Pinus ponderosa Dougl. ex P. & C. Laws. with zero (control), moderate, heavy, and severe crown scorch. The quantity of ethanol increased with each level of injury, resulting in trees with severe scorch containing 15 and 53 times more phloem and sapwood ethanol, respectively, than controls. Ethanol concentrations in the sapwood and adjacent phloem were related, probably as a result of diffusion. Upward movement in xylem sap was most likely responsible for the relationship between sapwood ethanol concentrations at breast height and the stem base. As trees recovered from their heat injuries, the ethanol concentrations declined. In contrast, ethanol accumulated in dead trees that lost their entire crowns in the fire. Various bark and xylophagous beetles landed in greater numbers on fire-damaged trees than on controls the following spring and summer, suggesting that ethanol was being released to the atmosphere and influencing beetle behavior. Beetle landing was more strongly related to sapwood ethanol concentrations the previous September than in May. Sapwood ethanol measured 16 days after the fire was the best predictor of second-year mortality for trees with heavy and severe crown scorch.


Weed Science ◽  
1982 ◽  
Vol 30 (1) ◽  
pp. 98-101 ◽  
Author(s):  
John C. Tappeiner ◽  
Steven R. Radosevich

An experiment was established in 1961 to determine the influence of bearmat (Chamaebatia foliolosa Benth.) competition on ponderosa pine (Pinus ponderosa Laws.) survival and growth. Ponderosa pine seedlings were planted in bearmat which was: (A) untreated, (B) sprayed with a mixture of 2,4-D [(2,4-dichlorophenoxy)acetic acid] and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], and (C) eliminated by a combination of herbicide, clipping sprouts, and trenching to prevent root and rhizome invasion. Ponderosa pine survival after 19 yr averaged 9%, 66%, and 90%, respectively, for the three treatments. Tree height after 19 yr averaged 1.6, 1.9, and 5.7 m for treatments A, B, and C, respectively. Soil moisture use was initially less on the herbicide-treated than on the untreated plots, but bearmat quickly sprouted after application to compete with the pine seedlings for moisture. After 19 yr the bearmat was more dense and appeared to be more vigorous on the sprayed plots than on those receiving no treatment. We estimate that 75% reduction in net wood production could result after 50 yr on this site from bearmat competition.


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.


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.


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