scholarly journals Root Growth Potential and Microsite Effects on Conifer Seedling Establishment in Northern Idaho

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 597
Author(s):  
Jacob A. Reely ◽  
Andrew S. Nelson

Environmental conditions and seedling quality interact to produce complex patterns of seedling survival and growth. Root growth potential (RGP) is one metric of seedling quality that can be rapidly measured prior to planting, but the correlation of RGP and seedling performance is not consistent across studies. Site factors including microsite objects that cast shade and competing vegetation can also influence seedling performance. We examined the effects of RGP, presence/absence of a microsite object, and competition cover on the survival and growth of three native conifers to the Inland Northwest, USA, over 5 years. We found that RGP had no effect on the survival or growth of western larch (Larix occidentalis), Douglas fir (Pseudotsuga menziesii var. glauca), and grand fir (Abies grandis) at a mesic north aspect site and a xeric south aspect site. Comparatively, the presence of a microsite increased the odds of survival by 37% for western larch and 158% for grand fir, while the absence of forb cover increased the odds of survival of western larch by 72% and of grand fir by 26%. Douglas fir was less sensitive to microsites and competition. The strong effects of neighborhood conditions around seedlings help inform silvicultural practices to enhance the establishment of western larch and grand fir, including planting seedlings near shading objects and competition control, while these practices may not be as important for Douglas fir.

1982 ◽  
Vol 12 (4) ◽  
pp. 905-912 ◽  
Author(s):  
Gary A. Ritchie

Carbohydrate reserves and root growth potential (RGP) of 2 + 0 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings were monitored through a lifting season and during dark, cold storage. Concentrations of total nonstructural carbohydrate and extractable sugars in root and stem tissues remained relatively constant through winter, while foliar sugars showed a sharp midwinter peak at about 195 mg•g−1 dry weight. RGP was lowest in November and March and peaked in January. During storage at +2 and −1 °C, carbohydrates were depleted in all tissues through respiratory consumption. In contrast, RGP increased during the first 6 months in storage and then fell rapidly. The results do not support the view that changes in RGP are driven by changes in carbohydrate concentrations. Storage may affect frost hardiness and drought resistance through its effect on sugar concentrations.


1989 ◽  
Vol 13 (4) ◽  
pp. 163-169 ◽  
Author(s):  
S. W. Hallgren ◽  
C. G. Tauer

Abstract Root growth potential (RGP), and first-year field survival and growth of shortleaf pine (Pinus echinata Mill.) seedlings were significantly affected by lift date, storage, and family. Seedlings lifted in December and January showed highest RGP, survival, and growth. Storage for 28 daysalways reduced survival and growth, and the effect was greatest for late-lifted seedlings. However, for late planting, the difference in performance between freshly lifted seedlings and earlier lifted and stored seedlings may be small. Large family differences existed for seasonal changesin RGP and survival, suggesting separate management by family may be beneficial. The presence of a terminal bud and secondary needles showed little value in predicting seedling performance, whereas RGP and number of primary lateral roots were strongly correlated with seedling survival. South.J. Appl. For. 13(4):163-169.


1995 ◽  
Vol 71 (6) ◽  
pp. 739-742 ◽  
Author(s):  
David G. Simpson ◽  
Alan Vyse

Douglas-fir [Pseudotsuga menziesii var glauca (Beissn.) Franco], interior spruce [Picea glauca Moench (Voss), Picea engelmannii (Parry) and their naturally occurring hybrids] and lodge-pole pine (Pinus contorta Dougl.) seedlings were planted on several forest sites in south central British Columbia. At planting, root growth potential (number of newly elongated roots longer than 10 mm per seedling) was determined. Trees were assessed for survival and height for at least five years. Survival of Douglas-fir and growth of all three species was affected by planting site, probably reflecting moisture and growing season temperature differences among sites. High (> 70%) survival, but not total height or mean annual relative growth rate was associated with root growth potential levels greater than 10 new roots per seedling in interior spruce and lodgepole pine. Survival and growth of Douglas-fir were not related to root growth potential. Fertilization of interior spruce seedlings at planting decreased survival 18% over seven growing seasons, and did not affect growth of surviving seedlings. Key words: reforestation, root growth potential, seedling quality, Douglas-fir, interior spruce, lodgepole pine, field performance


1986 ◽  
Vol 16 (6) ◽  
pp. 1385-1388 ◽  
Author(s):  
Paul M. Tabbush

Sealed bags containing forty 2-year-old Sitka spruce (Piceasitchensis (Bong.) Carr.) transplants were dropped 1–15 times from a height of 3 m onto a hard floor. A single drop reduced root growth potential of the plants as measured by a 10-day test, although after 18 days' growth the effect was no longer detectable. Dropping the bags 5 or 15 times severely decreased root growth potential even in the 18-day test. The 15-drop treatment significantly depressed 1-year survival of samples planted in the nursery. Sitka spruce and Douglas-fir (Pseudotsugamenziesii fMirb.) Franco.) transplants dropped 10 times, together with control plants, were placed in root observation boxes with an air temperature of 8 °C and a soil temperature of 4, 8, 12, or 16 °C. At 4 °C soil temperature, little or no root growth was observed in either species. At the higher temperatures the total numbers of new roots formed in 10 days and the number of new roots greater than 1 cm in length formed in 18 days were generally greater in Sitka spruce than Douglas-fir. In both species, root growth was sharply reduced by the mechanical shock treatment. Dropping the trees also depressed mycorrhizal development and resulted in a significant lowering of predawn water potential in Douglas-fir.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ehren Reid Von Moler ◽  
Andrew Steven Nelson

As the demand for drought hardy tree seedlings rises alongside global temperatures, there is a need to optimize nursery drought preconditioning methods to improve field performance of planted seedlings. This perspective article advocates for a more holistic approach to drought preconditioning research that considers the moderating role of plant developmental stage on the effects of drought preconditioning. We identify discrepancies in past studies of root growth potential (RGP) responses to drought preconditioning and highlight studies that suggest such discrepancies may result from inconsistencies among studies in the timing of drought preconditioning implementation. We then illustrate our perspective by presenting original research from an aeroponic RGP trial of 1st-year western larch (Larix occidentalis Nutt.) seedlings exposed to three soil moisture contents for 6months. We evaluated whether drought preconditioning could be used to increase the ratio of root: foliar tissue mass or enhance seedling physiological vigor during a subsequent growth period. Drought preconditioning was found to increase the ratio of root: foliar tissue mass and enhance seedling physiological vigor. Specifically, soil moisture content related negatively with new root biomass, positively with new foliar biomass, and negatively with the length and number of new roots (p<0.001). Meanwhile, the mass of lateral root production following drought preconditioning, but prior to aeroponic growth, correlated weakly to the mass, count, and length of new roots produced during aeroponic growth. We propose that evaluating the importance of the timing of drought preconditioning treatments constitutes an important research frontier in plant science.


1990 ◽  
Vol 63 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. D. DEANS ◽  
C. LUNDBERG ◽  
M. G. R. CANNELL ◽  
M. B. MURRAY ◽  
L. J. SHEPPARD

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