Plant Water Stress and Soil Depletion in Variable-Density, Red Alder/Western Hemlock Coastal Oregon Plantations

2019 ◽  
Vol 66 (3) ◽  
pp. 304-313
Author(s):  
Elizabeth C Cole ◽  
Michael Newton
Keyword(s):  
Water Stress ◽  
Summer Precipitation ◽  
Growing Season ◽  
Variable Density ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Riparian Ecosystems ◽  
Replacement Series ◽  
Red Alder ◽  
The Impact

Abstract Riparian ecosystems provide critical habitat and functions while being some of the most productive areas in forests. Both conifers and hardwoods contribute to maintenance of habitat and function. To determine the impact of water stress on growth of red alder (Alnus rubra Bong.) and western hemlock (Tsuga heterophylla [Raf.] Sarg.), we installed Nelder type 1a combined with replacement series plots on three Oregon Coast Range sites. Densities ranged from 988 to 85,400 trees/hectare, with ratios (hemlock:alder) of 100:0, 75:25, 50:50, 25:75, and 0:100. In the first 4 years after planting, alder used water in the growing season at greater depths earlier than western hemlock. Higher densities resulted in greater water stress later in the growing season in weeded areas (maintained by herbicide applications), but stress was similar across densities in unweeded areas. Water stress at early ages was correlated with decreased size 14 or 24 years after planting for both species, but these correlations were confounded with other effects of density. Increasing water availability in areas with low summer precipitation could enhance growth of red alder and western hemlock, even in highly productive riparian areas.

Canopy disturbances over the five-century lifetime of an old-growth Douglas-fir stand in the Pacific Northwest

2002 ◽  
Vol 32 (6) ◽  
pp. 1057-1070 ◽  
Author(s):  
Linda E Winter ◽  
Linda B Brubaker ◽  
Jerry F Franklin ◽  
Eric A Miller ◽  
Donald Q DeWitt
Keyword(s):  
Pacific Northwest ◽  
Variable Density ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Old Growth ◽  
The Pacific ◽  
History Of ◽  
Horizontal Heterogeneity ◽  
Restoration Strategies

The history of canopy disturbances over the lifetime of an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand in the western Cascade Range of southern Washington was reconstructed using tree-ring records of cross-dated samples from a 3.3-ha mapped plot. The reconstruction detected pulses in which many western hemlock (Tsuga heterophylla (Raf.) Sarg.) synchronously experienced abrupt and sustained increases in ringwidth, i.e., "growth-increases", and focused on medium-sized or larger ([Formula: see text]0.8 ha) events. The results show that the stand experienced at least three canopy disturbances that each thinned, but did not clear, the canopy over areas [Formula: see text]0.8 ha, occurring approximately in the late 1500s, the 1760s, and the 1930s. None of these promoted regeneration of the shade-intolerant Douglas-fir, all of which established 1500–1521. The disturbances may have promoted regeneration of western hemlock, but their strongest effect on tree dynamics was to elicit western hemlock growth-increases. Canopy disturbances are known to create patchiness, or horizontal heterogeneity, an important characteristic of old-growth forests. This reconstructed history provides one model for restoration strategies to create horizontal heterogeneity in young Douglas-fir stands, for example, by suggesting sizes of areas to thin in variable-density thinnings.

Use of growth curve derivatives to illustrate acceleration and deceleration of growth in young plantations under variable competition

2006 ◽  
Vol 36 (10) ◽  
pp. 2515-2522 ◽  
Author(s):  
Michael Newton ◽  
Elizabeth C Cole
Keyword(s):  
Growth Period ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Early Years ◽  
Western Hemlock ◽  
Richards Equation ◽  
Second Derivative ◽  
Red Alder ◽  
Vegetation Control ◽  
Second Derivatives

Deceleration of growth rates can give an indication of competition and the need for thinning in early years but can be difficult to detect. We computed the first and second derivatives of the von Bertalanffy – Richards equation to assess impacts of density and vegetation control in young plantations in western Oregon. The first derivative describes the response in growth and the second derivative describes the change in growth over time. Three sets of density experiments were used: (i) pure Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), (ii) mixed Douglas-fir and grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), and (iii) mixed western hemlock (Tsuga heterophylla (Raf.) Sarg.) and red alder (Alnus rubra Bong.). Original planting densities ranged from 475 to 85 470 trees·ha–1 (4.6 m × 4.6 m to 0.34 m × 0.34 m spacing); western hemlock and red alder plots were weeded and unweeded. For the highest densities, the second derivative was rarely above zero for any of the time periods, indicating that the planting densities were too high for tree growth to enter an exponential phase. As expected, the lower the density, the greater and later the peak in growth for both the first and second derivatives. Weeding increased the growth peaks, and peaks were reached earlier in weeded than in unweeded plots. Calculations of this sort may help modelers identify when modifiers for competition and density are needed in growth equations. Specific applications help define onset of competition, precise determining of timing of peak growth, period of acceleration of growth, and interaction of spacing and age in determination of peaks of increment or acceleration or deceleration.

First-year survival of Tsuga heterophylla without mycorrhizae and subsequent ectomycorrhizal development on decaying logs and mineral soil

1982 ◽  
Vol 60 (9) ◽  
pp. 1601-1605 ◽  
Author(s):  
E. Jennifer Christy ◽  
Phillip Sollins ◽  
James M. Trappe
Keyword(s):  
Mineral Soil ◽  
Root Systems ◽  
Growing Season ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
First Year ◽  
Cenococcum Geophilum ◽  
Piloderma Croceum

Roots of western hemlock (Tsuga heterophylla) seedlings 1–5+ years old that had established naturally on logs in three states of decay or on mineral soil were compared for numbers and kinds of ectomycorrhizae. Mycobionts colonizing root systems included Cenococcum geophilum Fr., Piloderma croceum (Bres.) Erikss. & Hjorts., and four unidentified fungi distinguished by color and morphology. About half the seedlings surviving the first growing season (2–7 months) were nonmycorrhizal. Nonmycorrhizal seedlings were most frequent on the least decayed logs. However, mycotrophy appeared to be advantageous to hemlock; 1st-year mycorrhizal seedlings had shoots 60% longer and roots 47% longer than 1st-year nonmycorrhizal seedlings. All 2nd-year and older seedlings were mycorrhizal. The ability of western hemlock to survive the first growing season without mycorrhizae may contribute to its success in colonizing decaying logs, which may contain microsites devoid of effective ectomycorrhizal inocula.

scholarly journals Effect of Spraying Salicylic Acid and Potassium on Sweet Pepper Growth under Water Stress

2018 ◽  
Vol 26 (8) ◽  
pp. 41-52 ◽  
Author(s):  
Ibrahim Mordhi Radhi ◽  
Haider Talib
Keyword(s):  
Salicylic Acid ◽  
Water Stress ◽  
Vegetative Growth ◽  
Growing Season ◽  
Sweet Pepper ◽  
Potassium Content ◽  
Randomized Design ◽  
The Impact ◽  
Living Area ◽  
Private Farm

         This experiment was conducted during the spring growing season 2017 in private farm of Babylon to study the impact of spraying salicylic acid , potassium under water stress and their interaction in sweet pepper growth under water stress. Plants were sprayed three times in 20 days intervals with three levels of Salicylic acid(SA) (0 ,50 and 100 mg. L-1) , three levels potassium with ( 0, 1000 and 2000 mg. L-1) and three irrigation times (5 ,10 ,15 )days. Complete Randomized Design (C.R.D ) with three replicates. Means were compared by L.S.D.O.O5 . Plant high, leaves the number, living area, Auxin(IAA) and potassium content increased with the increase in SA, K concentrations, D1 and interaction between them. D3 significantly decreased vegetative growth and IAA, but increased proline, catalase, SOD and ABA. Also, most of the characters were significantly influenced by an interaction between D3, SA and K concentrations.

Growth limitations of planted conifers regenerating under Montane Alternative Silviculture Systems (MASS): Seven-year results

2004 ◽  
Vol 80 (2) ◽  
pp. 241-250 ◽  
Author(s):  
A K Mitchell ◽  
B G Dunsworth ◽  
J T Arnott ◽  
R. Koppenaal ◽  
R. Benton ◽  
...  
Keyword(s):  
Treatment Time ◽  
Tsuga Heterophylla ◽  
Height Growth ◽  
Western Hemlock ◽  
Initial Growth ◽  
Vegetation Control ◽  
Abies Amabilis ◽  
Silvicultural System ◽  
The Impact ◽  
Effect On Growth

As part of the Montane Alternative Silviculture Systems (MASS) project, this study investigates limits on the growth of montane conifers resulting from varying overstory retention under conventional and alternative silvicultural systems. After harvesting treatments were complete in 1993, Abies amabilis (amabilis fir) and Tsuga heterophylla (western hemlock) seedlings were spring planted in replicated blocks of shelterwood (SW), patch cut (PC), green tree retention (GT) and clearcut (CC) systems. In addition, sub-plots were established within each silvicultural system in which fertilization (at planting) and vegetation control post-planting treatments were applied alone and in combination to test the extent to which growth limitations are related to nutrient availability and vegetative competition. The impact of overstory retention was most pronounced in the reduced light environment of the SW where height growth after seven years was 26-30% lower in both species compared to the untreated CC, GT and PC systems. Although the effect on growth of both species in the SW was mitigated somewhat by fertilization and vegetation control treatments, amabilis fir did not attain free-to-grow height (1.3 m) regardless of post-planting treatment. Time to free-to-grow height in the more open silvicultural systems was reduced in both fir and hemlock with fertilization and vegetation control alone and in combination, except in the CC where the initial growth response to fertilization alone was diminished by the end of the seven-year study. In contrast to fertilization, the effects of vegetation control on height growth were not apparent until three to five years and seven years after planting in the CC and GT, PC, SW, respectively. Combining vegetation control and fertilization had an additive effect on growth in amabilis fir but not in western hemlock. The effect of silvicultural systems and post-planting treatments on the two species illustrate that both above- and below-ground resource availability (light and nutrients) availability was potentially limiting to growth, particularly in the shelterwood treatment. Key words: MASS, silviculture systems, regeneration, Tsuga heterophylla, Abies amabilis, shelterwood, patch cut, green tree reten-tion, clearcut, fertilizer, vegetation control

Flowering response of western hemlock seedlings to gibberellin and water-stress treatments

1982 ◽  
Vol 12 (1) ◽  
pp. 76-82 ◽  
Author(s):  
H. Brix ◽  
F. T. Portlock
Keyword(s):  
Water Stress ◽  
Foliar Spray ◽  
Growing Season ◽  
Tree Improvement ◽  
Western Hemlock ◽  
Breeding Cycle ◽  
Soil Drying ◽  
Operational Application ◽  
Improvement Programs ◽  
Natural Breeding

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings, 1–5 years old, were treated with various numbers and durations of soil-drying cycles alone or in combination with a weekly foliar spray of 200 mg/L of a gibberellin A4/7 mixture. Control plants did not flower and water stress alone did not promote flowering. Only sparse flowering was produced with GA4/7 alone but when this was applied with two soil-drying cycles during the 7-week treatment period from mid-June through July an average of seven strobili per plant were induced on one-half of the 1-year-old seedlings (during their second growing season). Two drying cycles were more effective than one, though similar maximum plant water stress at predawn, −25 bars (1 bar = 100 kPa), was attained in both treatments. For the 4-year-old seedlings, 60% flowered, with an average of 64 strobili per plant. As many male as female strobili were produced on the average for all seedling groups. An operational application of these treatments to substantially shorten the natural breeding cycle in tree improvement programs is feasible.

Red spruce seedling gas exchange in response to elevated CO2, water stress, and soil fertility treatments

1994 ◽  
Vol 24 (5) ◽  
pp. 954-959 ◽  
Author(s):  
L.J. Samuelson ◽  
J.R. Seiler
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Soil Fertility ◽  
Net Photosynthesis ◽  
Growing Season ◽  
Red Spruce ◽  
Fertility Treatment ◽  
Sink Strength ◽  
Growth Enhancement ◽  
Growing Seasons

The interactive influences of ambient (374 μL•L−1) or elevated (713 μL•L−1) CO2, low or high soil fertility, well-watered or water-stressed treatment, and rooting volume on gas exchange and growth were examined in red spruce (Picearubens Sarg.) grown from seed through two growing seasons. Leaf gas exchange throughout two growing seasons and growth after two growing seasons in response to elevated CO2 were independent of soil fertility and water-stress treatments, and rooting volume. During the first growing season, no reduction in leaf photosynthesis of seedlings grown in elevated CO2 compared with seedlings grown in ambient CO2 was observed when measured at the same CO2 concentration. During the second growing season, net photosynthesis was up to 21% lower for elevated CO2-grown seedlings than for ambient CO2-grown seedlings when measured at 358 μL•L−1. Thus, photosynthetic acclimation to growth in elevated CO2 occurred gradually and was not a function of root-sink strength or soil-fertility treatment. However, net photosynthesis of seedlings grown and measured at an elevated CO2 concentration was still over 2 times greater than the photosynthesis of seedlings grown and measured at an ambient CO2 concentration. Growth enhancement by CO2 was maintained, since seedlings grown in elevated CO2 were 40% larger in both size and weight after two growing seasons.

scholarly journals Beavers, Bugs and Chemistry: A Mammalian Herbivore Changes Chemistry Composition and Arthropod Communities in Foundation Tree Species

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 877
Author(s):  
Rachel M. Durben ◽  
Faith M. Walker ◽  
Liza Holeski ◽  
Arthur R. Keith ◽  
Zsuzsi Kovacs ◽  
...  
Keyword(s):  
Tree Species ◽  
Castor Canadensis ◽  
Habitat Type ◽  
Food Preferences ◽  
Woody Species ◽  
Juvenile Growth ◽  
Arthropod Community ◽  
Riparian Ecosystems ◽  
Arthropod Communities ◽  
The Impact

The North American beaver (Castor canadensis Kuhl) and cottonwoods (Populus spp.) are foundation species, the interactions of which define a much larger community and affect a threatened riparian habitat type. Few studies have tested the effect of these interactions on plant chemistry and a diverse arthropod community. We experimentally examined the impact of beaver foraging on riparian communities by first investigating beaver food preferences for one cottonwood species, Fremont cottonwood (P. fremontii S. Watson), compared to other locally available woody species. We next examined the impact of beaver foraging on twig chemistry and arthropod communities in paired samples of felled and unfelled cottonwood species in northern Arizona (P. fremontii) and southwestern Colorado (narrowleaf cottonwood, P. angustifolia James, and Eastern cottonwood, P. deltoides W. Bartram ex Marshall). Four major patterns emerged: (1) In a cafeteria experiment, beavers chose P. fremontii six times more often than other woody native and exotic species. (2) With two cottonwood species, we found that the nitrogen and salicortin concentrations were up to 45% greater and lignin concentration 14% lower in the juvenile resprout growth of felled trees than the juvenile growth on unfelled trees (six of seven analyses were significant for P. fremontii and four of six were significant for P. angustifolia). (3) With two cottonwood species, arthropod community composition on juvenile branches differed significantly between felled and unfelled trees, with up to 38% greater species richness, 114% greater relative abundance and 1282% greater species diversity on felled trees (six of seven analyses with P. fremontii and four of six analyses with P. angustifolia were significant). The above findings indicate that the highest arthropod diversity is achieved in the heterogenous stands of mixed felled and unfelled trees than in stands of cottonwoods, where beavers are not present. These results also indicate that beaver herbivory changes the chemical composition in 10 out of 13 chemical traits in the juvenile growth of two of the three cottonwood species to potentially allow better defense against future beaver herbivory. (4) With P. deltoides, only one of five analyses in chemistry was significant, and none of the four arthropod community analyses were significant, suggesting that this species and its arthropod community responds differently to beaver. Potential reasons for these differences are unknown. Overall, our findings suggest that in addition to their impact on riparian vegetation, other mammals, birds, and aquatic organisms, beavers also may define the arthropod communities of two of three foundation tree species in these riparian ecosystems.

scholarly journals The Impact of Climate Change on the Sugar Content of Grapes and the Sustainability of their Production in the Czech Republic

2020 ◽  
Vol 13 (1) ◽  
pp. 222
Author(s):  
Miroslava Navrátilová ◽  
Markéta Beranová ◽  
Lucie Severová ◽  
Karel Šrédl ◽  
Roman Svoboda ◽  
...  
Keyword(s):  
Climate Change ◽  
Czech Republic ◽  
Sugar Content ◽  
Growing Season ◽  
Vegetation Period ◽  
The Czech Republic ◽  
Impact Of Climate Change ◽  
Secondary Sources ◽  
The Impact ◽  
Growing Region

The aim of the presented article is to evaluate the impact of climate change on the sugar content of grapes in the Czech Republic during the period 2000–2019 through selected indicators on the basis of available secondary sources. Attention is focused on the developments in both the main wine-growing regions of Moravia and Bohemia. In the field of viticulture and wine-growing, the sugar content of grapes, as a basic parameter for the classification of wines, plays an important role. In the Czech Republic, the average sugar content of grapes has had a constantly growing trend. This trend is evident both in the wine-growing region of Bohemia and in the wine-growing region of Moravia. The impact of climate change, especially the gradual increase of average temperatures in the growing season, cannot be overlooked. It greatly affects, among other things, the sugar content of grapes. Calculations according to the Huglin Index and the Winkler Index were used to determine the relationship between climate and sugar content. These indexes summarize the course of temperatures during the entire vegetation period into a single numerical value. The results show that both indexes describe the effect of air temperature on sugar content in both wine regions of the Czech Republic in a statistically significant way. The Huglin Index shows a higher correlation rate. The Winkler Index proved to be less suitable for both areas. Alternatively, the Winkler Index calculated for a shorter growing season was tested, which showed a higher degree of correlation with sugar content, approaching the significance of the Huglin Index.

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