Seasonal changes in biomass and vertical distribution of mycorrhizal and fibrous-textured conifer fine roots in 23- and 180-year-old subalpine Abiesamabilis stands

1981 ◽  
Vol 11 (2) ◽  
pp. 224-230 ◽  
Author(s):  
Kristiina A. Vogt ◽  
Robert L. Edmonds ◽  
Charles C. Grier
Keyword(s):  
Root Growth ◽  
Vertical Distribution ◽  
Seasonal Changes ◽  
Forest Floor ◽  
Fine Roots ◽  
Early Spring ◽  
Silver Fir ◽  
Growing Up ◽  
Young Stand ◽  
Mycorrhizal Roots

Seasonal changes in biomass and vertical distribution of fibrous, mycorrhizal, and total conifer fine roots (≤ 2 mm) were examined in 23- and 180-year-old Pacific silver fir (Abiesamabilis (Dougl.) Forbes) ecosystems. In both stands, > 80% of fine roots was located in the upper 15 cm of the soil profile, in the forest floor (O1 and O2) and A horizon. During periods of active root growth in the young stand, significantly higher conifer root biomass occurred in the A horizon (370 to 690 g/m2) than the forest floor (200 to 350 g/m2). At all sampling times, a significantly higher biomass of conifer fine roots was located in the forest floor (550 to 1090 g/m2) than the A horizon (290 to 640 g/m2) in the old stand. In both stands, mycorrhizal roots comprised 10 to 15% of the total weight of conifer fine roots during peak root growth, 2 to 6% when roots were not growing, and 21 to 29% during the winter and early spring when roots were growing. Up to 69% of the biomass of fibrous and mycorrhizal roots was located in the forest floor in both stands.

Seasonal changes in mycorrhizal and fibrous-textured root biomass in 23- and 180-year-old Pacific silver fir stands in western Washington

1980 ◽  
Vol 10 (4) ◽  
pp. 523-529 ◽  
Author(s):  
Kristiina A. Vogt ◽  
Robert L. Edmonds ◽  
Charles C. Grier ◽  
Stephen R. Piper
Keyword(s):  
Seasonal Changes ◽  
Root Biomass ◽  
Fine Root Biomass ◽  
Early Summer ◽  
Silver Fir ◽  
Fibrous Root ◽  
Mycorrhizal Root ◽  
Young Stand ◽  
Soil Temperatures ◽  
Mycorrhizal Roots

Seasonal changes in mycorrhizal and fibrous root biomass were examined in 23- and 180-year-old Abiesamabilis (Dougl.) Forbes stands. Both stands had similar patterns of change in mycorrhizal root biomass with the lowest level in the summer and highest in the fall. The fall peak of fine root biomass was the result of increased mycorrhizal and not fibrous root biomass. High levels of active mycorrhizal root biomass were measured during the winter months under a snowpack at soil temperatures of 1 °C. In both stands mycorrhizal roots comprised the largest proportion of the weight of fine roots during the winter (29%) and the lowest during the summer (2%). Except during early summer, the old stand had significantly higher levels of mycorrhizal root biomass in comparison to the young stand throughout the year.

Distribution and chemistry of fine roots in a white spruce – subalpine fir stand in British Columbia: implications for management

1978 ◽  
Vol 8 (3) ◽  
pp. 265-279 ◽  
Author(s):  
J. P. Kimmins ◽  
B. C. Hawkes
Keyword(s):  
Vertical Distribution ◽  
Forest Floor ◽  
Fine Roots ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Root Tips ◽  
Subalpine Fir ◽  
Chemical Content ◽  
The Vertical Distribution

The vertical distribution of fine-root biomass, its chemical content, and the vertical distribution of overstory root tips were measured in a mature white spruce – subalpine fir stand (Piceaglauca (Moench) Voss – Abieslasiocarpa (Hook.) Nutt.) growing on an infertile sandy soil near Prince George, British Columbia, during July and August, 1975. The study was part of a larger project which described the biomass and chemical content of the tree and minor vegetation. The objective of the project was to provide information on nutrient losses accompanying whole-tree logging and to estimate the possible consequences of such losses for future tree production. Questions concerning the magnitude of the soil nutrient capital available to the vegetation indicated the need for information on the exploitation of the soil by the roots. This paper reports the results of an investigation of the fine roots. Living fine roots (<6.4 mm) of overstory trees and understory plants were sampled separately from 11 soil pits to an average depth of 94 cm. Overstory fine-root biomass was estimated to be about 1870 kg/ha of which 67% was in the forest floor (LFH horizon) and the Ae horizon. The average combined depth of these two horizons was only 8.3 cm, but they contained 88% of the overstory root tips sampled. The 3.3-cm-thick forest floor alone contained half of the fine-root biomass and approximately 70% of the overstory root tips. Understory fine-root biomass was estimated to be about 7880 kg/ha of which 69% was in the forest floor and the Ae horizon. The concentrations of N, P, K, Ca, and Mg generally decreased with increasing depth, while Fe and Al exhibited the opposite pattern.The marked concentration of fine-root biomass and root tips in the forest floor is interpreted as reflecting the very low nutrient status of the mineral soil on the study site. The high value of fine-root biomass for understory vegetation results from the open structure of the stand and is thought to reflect the great importance of this vegetation in nutrient cycling on the study site. The biomass data, together with root chemical concentration data, are consistent with the hypothesis that the forest floor is the major source of several of the macronutrients for the vegetation on the site.

Fine-root distribution of coniferous plantations in relation to site in southern Buenos Aires, Argentina

1992 ◽  
Vol 22 (11) ◽  
pp. 1575-1582 ◽  
Author(s):  
Adrián Ares ◽  
Norman Peinemann
Keyword(s):  
Organic Matter ◽  
Vertical Distribution ◽  
Root Distribution ◽  
Fine Roots ◽  
Buenos Aires ◽  
Fine Root ◽  
Organic Matter Content ◽  
Root Density ◽  
Site Quality ◽  
Coniferous Plantations

A study was conducted to determine the amounts and vertical distribution of fine roots <2 mm as a function of site quality in a temperate, hilly zone of Argentina. Fine roots were sampled in autumn from 0.2-ha plots established in 12 coniferous plantations of Pinushalepensis Mill., Pinusradiata D. Don, Cedrusdeodara (D. Don) G. Don, and Cupressussempervirens L.f. horizontalis, located in Sierra de la Ventana, southern Buenos Aires. Generally, root density was found to be higher under low-growth stands. The distance from a tree sometimes had an effect on root density, but no clear pattern within stands could be observed. Root density commonly decreased with depth, but slight irregularities in some profiles were observed. Site quality and soil type influenced root distribution. Belowground biomass up to a depth of 50 cm ranged from 1600 to 9800 kg•ha−1 in high-growth stands and from 5400 to 40 700 kg•ha−1 in low-growth stands. Soil organic matter content provided the best correlation with root density. A possible practical implication would be the use of indices related to vertical distribution of organic matter, among other variables, as complementary estimators of effective depth of rooting. The results strongly suggest that trees maintain a large fine-root system in poor sites at the expense of aboveground growth.

scholarly journals Desiccation Tolerance of Green Ash and Sugar Maple Fine Roots

2009 ◽  
Vol 27 (4) ◽  
pp. 229-233 ◽  
Author(s):  
Gary W. Watson
Keyword(s):  
Root Growth ◽  
Fine Roots ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Fine Root ◽  
Cell Damage ◽  
Fraxinus Pennsylvanica ◽  
Green Ash ◽  
Root Electrolyte Leakage ◽  
Bare Root

Abstract Exposed fine roots are subject to desiccation, which may affect their survival as well as new root growth following bare root transplanting. Fine roots of dormant 1-year-old green ash (Fraxinus pennsylvanica) and sugar maple (Acer saccharum) seedlings, subjected to desiccation treatments of 0, 1, 2, or 3 hours in December and March, lost up to 82 percent of their water. Root electrolyte leakage, a measure of cell damage, tripled after three hours of desiccation. The increase was moderately, but significantly, greater in March for both species. Desiccation treatments had no effect on fine root survival. Growth of new roots (RGP) was also unaffected by desiccation treatments. RGP of maple was greater in March than December, but not ash.

Seasonal changes in serum thyroid hormone levels in ruffed grouse maintained under natural conditions of temperature and photoperiod

1979 ◽  
Vol 57 (10) ◽  
pp. 2022-2027 ◽  
Author(s):  
A. Garbutt ◽  
J. F. Leatherland ◽  
A. L. A. Middleton
Keyword(s):  
Thyroid Hormone ◽  
Seasonal Changes ◽  
Gonadal Development ◽  
Early Spring ◽  
Light Period ◽  
Ruffed Grouse ◽  
Natural Conditions ◽  
Blood Samples ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels

Serum triiodothyronine (T3) and thyroxine (T4) concentrations were measured in a population of ruffed grouse, held outdoors under natural conditions of photoperiod and temperature. Blood samples were collected at monthly intervals, and at the solstices and equinoxes to test for variation through the light period. No changes in T4 or T3 levels were found during the light period but levels of T3 and T4 showed marked seasonal changes. Lowest T4 and T3 levels were found in birds during the winter months, with an increase in the concentration of both hormones in early spring concomitant with gonadal development in the adults. A lowering of serum T4 and T3 values was associated with the period of molt.

Seasonal changes in concentrations of plasma hormones in the male ring dove (Streptopelia risoria)

1986 ◽  
Vol 108 (3) ◽  
pp. 385-391 ◽  
Author(s):  
R. W. Lea ◽  
P. J. Sharp ◽  
H. Klandorf ◽  
S. Harvey ◽  
I. C. Dunn ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Plasma Corticosterone ◽  
Early Spring ◽  
Energy Requirements ◽  
Breeding Cycle ◽  
Plasma Prolactin ◽  
Winter Solstice ◽  
Natural Lighting ◽  
Short Day ◽  
Ring Dove

ABSTRACT Seasonal changes in concentrations of plasma LH, prolactin, thyroxine (T4), GH and corticosterone were measured in captive male ring doves exposed to natural lighting at latitude 56 °N. Plasma LH levels decreased steeply in autumn when the daylength fell below about 12·5 h but increased in November as the birds became short-day refractory. In comparison with plasma LH concentrations in a group of short-day refractory birds exposed to 6 h light/day from the winter solstice, plasma LH levels in birds exposed to natural lighting increased further in spring after the natural daylength reached about 12·5 h. There were no seasonal changes in plasma prolactin concentrations and plasma T4 concentrations were at their highest during December, January and February, the coldest months of the year. The seasonal fall in plasma LH levels in September was associated with a transitory increase in plasma T4, a transitory decrease in plasma corticosterone and a sustained increase in plasma GH. It is suggested that in the ring dove, short-day refractoriness develops rapidly in November to allow the bird to breed when the opportunity arises, during the winter and early spring. The annual breeding cycle is synchronized by a short-day induced regression of the reproductive system in the autumn, the primary function of which may be to enable the birds to meet the energy requirements for the annual moult. The changes in plasma T4, corticosterone and especially of GH at this time of year are probably concerned with the control of moult or the associated changes in energy requirements. J. Endocr. (1986) 108, 385–391

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