Effects of contrasting light and soil moisture availability on the growth and biomass allocation of Douglas-fir and red alder

2003 ◽  
Vol 33 (1) ◽  
pp. 106-117 ◽  
Author(s):  
Samuel S Chan ◽  
Steven R Radosevich ◽  
Amy T Grotta
Keyword(s):  
Soil Moisture ◽  
Biomass Allocation ◽  
Competitive Ability ◽  
Field Capacity ◽  
Douglas Fir ◽  
Red Alder ◽  
Moisture Availability ◽  
Biomass Components ◽  
Soil Moisture Availability ◽  
Moisture Conditions

We examined growth and biomass allocation of individual Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and red alder (Alnus rubra Bong.) seedlings grown for 3 years under contrasting combinations of light and water. Alder growth was always greater than Douglas-fir. Full sunlight and soil moisture at field capacity caused large differences in size between the two species. With limited light and water, differences were smaller. Under full light and limited water, Douglas-fir allocated a high portion of its biomass to roots, whereas red alder allocated a high percentage to aboveground biomass components. Under light and water resource-limiting situations, red alder allocated more mass to stem, whereas Douglas-fir allocated more to roots. Red alder growth responded negatively to water limitation, whereas Douglas-fir did not. Red alder exhibited greater foliage plasticity to light. Species differences in size and allocation in response to resource availability may determine pathways by which Douglas-fir and red alder interact in a mixed community. Our findings support the hypothesis that the potential of species to use growth-limiting resources is an indicator of competitive ability. We suggest that red alder and Douglas-fir can co-exist under conditions of full light and limiting soil moisture availability. Furthermore, when contrasted with red alder, Douglas-fir's relatively greater tolerances to low light allow it to better persist in the understory. Red alder's rapid early growth and competitive ability will be superior under full light and nonlimiting soil moisture conditions.

Seasonal variation in competitive effect on water stress and pine responses

1994 ◽  
Vol 24 (7) ◽  
pp. 1440-1449 ◽  
Author(s):  
M.A. Perry ◽  
R.J. Mitchell ◽  
B.R. Zutter ◽  
G.R. Glover ◽  
D.H. Gjerstad
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Volume Index ◽  
Integral Approach ◽  
Stem Volume ◽  
Competitive Effects ◽  
Moisture Availability ◽  
Soil Moisture Availability

Plant mixtures were established that differed in both proportion and density of loblolly pine (Pinustaeda L.), sweetgum (Liquidambarstyraciflua L.), and broomsedge (Andropogonvirginicus L.). Soil moisture availability to the pine seedlings was quantified every 2 weeks by measuring predawn xylem pressure potentials. Temporal variation in pine water potential was accounted for by a water stress integral approach. Cumulative water stress integral values were calculated over four overlapping periods, from May to June, May to July, May to August, and May to September and compared with the mean seedling stem volume index at each period to determine competitive responses at the whole plant scale. Diurnal measures of stomatal conductance were taken each month to compare competitive responses at the leaf scale. In addition, environmental and plant responses that may control stomatal behavior were quantified. The pine water stress integral was strongly influenced by competing vegetation after the onset of a period of drought in early summer. The correlation between the water stress integral and pine growth increased after a significant drying period, accounting for more than half of the variation in stem volume index at the end of the first growing season. Stomatal conductance was also influenced by competition, with competitive effects more evident during times of drought. Conductance was most often related to bulk leaf water potential, which in turn was related to competitive effects on soil moisture availability. Vapor pressure deficit also influenced stomatal conductance, but this was largely unrelated to competitive effects.

Carbon accumulation in loblolly pine plantations is increased by fertilization across a soil moisture availability gradient

2018 ◽  
Vol 424 ◽  
pp. 39-52 ◽  
Author(s):  
Rosvel Bracho ◽  
Jason G. Vogel ◽  
Rodney E. Will ◽  
Asko Noormets ◽  
Lisa J. Samuelson ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Loblolly Pine ◽  
Carbon Accumulation ◽  
Pine Plantations ◽  
Moisture Availability ◽  
Soil Moisture Availability

scholarly journals Splitting the Difference: Heterogeneous Soil Moisture Availability Affects Aboveground and Belowground Reserve and Mass Allocation in Trembling Aspen

2021 ◽  
Vol 12 ◽  
Author(s):  
Ashley T. Hart ◽  
Morgane Merlin ◽  
Erin Wiley ◽  
Simon M. Landhäusser
Keyword(s):  
Soil Moisture ◽  
Root System ◽  
Resource Availability ◽  
Moisture Regime ◽  
Trembling Aspen ◽  
Moisture Availability ◽  
Resource Limited ◽  
Heterogeneous Soil ◽  
Soil Moisture Availability ◽  
The Impact

When exploring the impact of resource availability on perennial plants, artificial treatments often apply conditions homogeneously across space and time, even though this rarely reflects conditions in natural systems. To investigate the effects of spatially heterogeneous soil moisture on morphological and physiological responses, trembling aspen (Populus tremuloides) saplings were used in a split-pot experiment. Following the division of the root systems, saplings were established for a full year and then subjected to either heterogeneous (portion of the root system exposed to non-lethal drought) or homogeneous (whole root system exposed to non-lethal drought or well-watered) treatments. Above- and belowground growth and non-structural carbohydrate (NSC) reserves (soluble sugars and starch) were measured to determine how allocation of reserves and mass between and within organs changed in response to variation in soil moisture availability. In contrast to saplings in the homogeneous drought treatment, which experienced reduced shoot growth, leaf abscission and fine root loss, saplings exposed to the heterogeneous conditions maintained similar aboveground growth and increased root system allocation compared to well-watered saplings. Interestingly under heterogeneous soil moisture conditions, the portion of the root system that was resource limited had no root dieback and increased carbon reserve concentrations, while the portion of the root system that was not resource limited added new roots (30% increase). Overall, saplings subjected to the heterogeneous soil moisture regime over-compensated belowground, both in mass and NSC reserves. These results indicate that the differential allocation of mass or reserves between above- and belowground organs, but also within the root system can occur. While the mechanisms and processes involved in these patterns are not clear, these responses could be interpreted as adaptations and acclimations to preserve the integrity of the entire sapling and suggests that different portions of plant organs might respond autonomously to local conditions. This study provides further appreciation of the complexity of the mechanisms by which plants manage heterogeneous conditions and offers evidence that spatial and temporal variability of resource availability, particularly belowground, needs to be accounted for when extrapolating and modeling stress responses at larger temporal and spatial scales.

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