Lateral Root Pruning – A Promising Forest Nursery Practice

1968 ◽  
Vol 44 (5) ◽  
pp. 12-13 ◽  
Author(s):  
S. Eis
Keyword(s):  
Lateral Root ◽  
Root Systems ◽  
Douglas Fir ◽  
Root Pruning ◽  
Height Increment ◽  
Forest Nursery

The regeneration and growth of pruned roots of Douglas-fir seedlings were studied under nursery conditions. Root pruning did not decrease the height increment of seedlings. For the best development of dense and compact root systems, the bottom pruning should be done early in spring and the side pruning around the middle of June, on both sides of the row simultaneously.

Lateral Root Pruning of Sitka Spruce and Western Hemlock Seedlings

1972 ◽  
Vol 2 (3) ◽  
pp. 223-227 ◽  
Author(s):  
S. Eis ◽  
J. R. Long
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Root Systems ◽  
Growing Season ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Short Length ◽  
Western Hemlock ◽  
Root Pruning

Roots of Sitka spruce (Picea sitchensis) and western hemlock (Tsugaheterophylla) seedlings were side pruned in nursery beds at semimonthly intervals to produce dense and compact root systems. Root pruning early in the growing season stimulated the growth of existing roots and also initiated new roots. The densest root systems were produced by pruning before the end of June. However, because of the short length of lateral roots on seedlings early in their second growing season, pruning equidistant between rows 18 cm apart was ineffective. The best compromise appeared to be to prune spruce at the beginning of July, and hemlock around the middle of July. Earlier pruning equidistant between rows can be effective on larger seedlings during their third growing season. If early pruning is carried out on 2 + 0 seedlings, a pruning distance of about 6 cm from the row is recommended.

Comparative root system morphologies of seeded-in-place, bareroot, and containerized Douglas-fir seedlings after outplanting

1979 ◽  
Vol 9 (3) ◽  
pp. 399-405 ◽  
Author(s):  
C. L. Preisig ◽  
W. C. Carlson ◽  
L. C. Promnitz
Keyword(s):  
Root System ◽  
Lateral Root ◽  
Root Systems ◽  
Douglas Fir ◽  
Tree Stability ◽  
Stock Type ◽  
Stock Types ◽  
Root Orientation

Root systems of 5- to 8-year-old Pseudotsugamenziesii (Mirb.) Franco seedlings of natural, bareroot, and container origin were quantitatively analyzed to determine the effects of seedling source on root system morphology. Lateral root orientation was stressed.Container and planting constrictions on root system morphology were recognizable after outplanting; planted stock types were differentiated from seeded-in-place seedlings on the basis of root system morphology. Container and natural seedlings had less variation in root system morphology within stock type than bareroot stock. Root spiraling was so low in the Douglas-fir stock types studies that it is not likely to affect tree stability. There was no overall effect of root system morphology on height of seedlings around 6 years of age.

scholarly journals Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 744-748 ◽  
Author(s):  
Jerry E. Weiland ◽  
Bryan R. Beck ◽  
Anne Davis
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seedling Survival ◽  
The United States ◽  
Douglas Fir ◽  
Tree Seedlings ◽  
Pythium Species ◽  
Forest Nursery ◽  
Damping Off ◽  
Greenhouse Study ◽  
Forest Nurseries

Pythium species are common soilborne oomycetes that occur in forest nursery soils throughout the United States. Numerous species have been described from nursery soils. However, with the exception of P. aphanidermatum, P. irregulare, P. sylvaticum, and P. ultimum, little is known about the potential for other Pythium species found in nursery soils to cause damping-off of tree seedlings. A greenhouse study was conducted to evaluate the pathogenicity and virulence of 44 Pythium isolates representing 16 species that were originally recovered from soil at three forest nurseries in Washington and Oregon. Seeds of Douglas-fir (Pseudotsuga menziesii) were planted into soil infested with each of the isolates. Seedling survival, the number of surviving seedlings with necrotic root lesions, and taproot length were evaluated 4 weeks later. Responses of Douglas-fir to inoculation varied significantly depending on Pythium species and isolate. Eight species (P. dissotocum, P. irregulare, P. aff. macrosporum, P. mamillatum, P. aff. oopapillum, P. rostratifingens, P. sylvaticum, and P. ultimum var. ultimum) significantly reduced the number of surviving seedlings compared to the noninoculated treatment. However, all Pythium species caused a greater percentage of seedlings to develop root lesions (total mean 40%) than was observed from noninoculated seedlings (17%). Taproot length varied little among Pythium treatments and was not a useful character for evaluating pathogenicity. Results confirm the ability of P. irregulare, P. mamillatum, and P. ultimum var. ultimum to cause damping-off of Douglas-fir seedlings, and are indicative that other species such as P. dissotocum, P. aff. macrosporum, P. aff. oopapillum, P. rostratifingens, and P. sylvaticum may also be responsible for seedling loss.

Effects of mechanical stimulus, shade, and nitrogen fertilization on morphology and bending resistance in Douglas-fir seedlings

2003 ◽  
Vol 33 (9) ◽  
pp. 1602-1609 ◽  
Author(s):  
Stephen J Mitchell
Keyword(s):  
Nitrogen Fertilization ◽  
Mechanical Stimulus ◽  
Douglas Fir ◽  
Height Increment ◽  
Stem Form ◽  
Diameter Increment ◽  
Reduced Height ◽  
Bending Resistance ◽  
Volume Increment ◽  
Bending Stresses

Three-year-old coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were planted in a factorial experiment with three levels of shading (0, 30, and 60%), three levels of mechanical stimulus (staked, freestanding, and bent), and two levels of nitrogen fertilization (0 and 200 kg/ha) to investigate the separate and combined effects of these factors on morphology and bending resistance. Fertilization increased branch angle and increased the sensitivity of branch and leader extension to bending stresses but did not affect volume increment, stem form, or bending resistance. The effects of shading and mechanical treatments on morphology were independent and additive. Shading reduced stem diameter and volume increment, but did not affect height increment, producing more slender trees. Bending produced less slender trees through a combination of reduced height increment and increased diameter increment. Staking did not affect tree morphology. Trees under heavy shade were responsive to bending but were more slender and had lower bending resistance than unshaded trees with the same mechanical stimulus. These results point towards the biological basis for the development of tree instability in high density stands.

Interaction between gibberellin A4/7 and root-pruning on the reproductive and vegetative processes in Douglas-fir. IV. Effects on lateral bud development

1986 ◽  
Vol 16 (2) ◽  
pp. 211-221 ◽  
Author(s):  
J. N. Owens ◽  
J. E. Webber ◽  
S. D. Ross ◽  
R. P. Pharis
Keyword(s):  
Normal Development ◽  
Shoot Elongation ◽  
Douglas Fir ◽  
Root Pruning ◽  
Lateral Shoot ◽  
Bud Development ◽  
Lateral Bud ◽  
Mitotic Frequency ◽  
Bud Initiation ◽  
Vegetative Bud

The anatomy, mitotic frequency, size, and total insoluble carbohydrate histochemistry was studied in axillary apices from 9- and 10-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees after cone induction treatments of root-pruning and (or) stem injections of a gibberellin A4 and A7 (GA4/7) mixture. Axillary buds were initiated at the time of root-pruning, but root-pruning treatment had no effect on axillary bud initiation. Axillary apices from control and gibberellin-treated trees were similar and followed the normal sequence of bud-scale initiation, differentiation, and leaf initiation (described previously) and no cone buds differentiated. Early development of axillary apices from root-pruned and root-pruned, gibberellin-treated trees was normal, but development became retarded near the time of vegetative bud flush. Retarded apices were small with low mitotic frequency and developed many features characteristics of latent apices. Retardation of axillary apices continued until mid-July when normal development resumed and apices differentiated into reproductive buds or vegetative buds, or became latent. The trees in which the greatest retardation of apical development occurred during lateral shoot elongation produced the most cone buds. These results are discussed in relation to hypotheses proposed to explain how cultural and gibberellin treatments affect cone induction in the Pinaceae.

Root systems of older immature hemlock, cedar, and Douglas-fir

1988 ◽  
Vol 18 (5) ◽  
pp. 657-657
Author(s):  
S. Eis
Keyword(s):  
Root Systems ◽  
Douglas Fir

not available

INFLUENCE OF ROOT PRUNING ON HEIGHT INCREMENT AND ROOT DEVELOPMENT OF OUTPLANTED SPRUCE

1967 ◽  
Vol 45 (9) ◽  
pp. 1671-1682 ◽  
Author(s):  
R. F. Sutton
Keyword(s):  
New York ◽  
Picea Glauca ◽  
First Year ◽  
Root Pruning ◽  
Silt Loam ◽  
Height Increment ◽  
Loam Soil ◽  
Second Year ◽  
Root Collar ◽  
Block Experiment

Three-year-old seedlings of Picea glauca and P. abies were outplanted in a fertile silt loam soil at Ithaca, New York, in a split-plot randomized block experiment involving large- and small-size classes of stock and four root-pruning treatments: control; laterals pruned to 5 cm; all roots pruned at 10 cm measured from the root collar; and all laterals pruned flush with the tap or main root.Survival was good except in the last treatment. First- and second-year height increments within each species were unaffected by root-pruning treatments, even the most extreme. This suggests that either water stress is not aggravated by root pruning or that root pruning has compensating advantages. In the second year, height increment of P. glauca was significantly inferior to that of the first year. Height increment of P. abies was significantly greater in the second than in the first year.Root systems of 20 P. glauca were excavated in the second year. Percentage increases of total root length (of all roots 1 cm or more long) in root-pruned trees were twice those of control trees. Highest values (> 1000%) were for vigorous trees in the moderate root-pruning treatments.

Twenty-year survival of Phellinus (Poria) weirii in Douglas-fir stumps

1976 ◽  
Vol 6 (2) ◽  
pp. 123-128 ◽  
Author(s):  
Everett M. Hansen
Keyword(s):  
Root Systems ◽  
Root Diameter ◽  
Douglas Fir ◽  
Hand Tools ◽  
Outer Limit ◽  
Dying Back

Fungus survival was examined in root systems of stumps of trees that were harvested 20 years previously. Roots were excavated with dynamite and hand tools to the outer limit of living P. weirii or until the roots went deeper than 45 cm. Sixty-nine stumps infected before harvest were excavated; P. weirii was still viable in 94%. The fungus was dying back in 68% of the stumps. Some roots as small as 1.3 cm had viable P. weirii, but the margin between living and dead P. weirii occurred at an average root diameter of 12.5 cm.The margin between living and dead P. weirii was often marked by a black zone line. The fungus survived only within roots with intact bark. Ectotrophic mycelium occurred in discontinuous patches on roots of 33% of the stumps.

Modeling in-situ pine root decomposition using data from a 60-year chronosequence

2002 ◽  
Vol 32 (9) ◽  
pp. 1675-1684 ◽  
Author(s):  
Kim H Ludovici ◽  
Stanley J Zarnoch ◽  
Daniel D Richter
Keyword(s):  
Loblolly Pine ◽  
Lateral Root ◽  
Lateral Roots ◽  
Nutrient Release ◽  
Root Systems ◽  
Root Decomposition ◽  
Good Precision ◽  
Clear Cut ◽  
Stump Diameter

Because the root system of a mature pine tree typically accounts for 20–30% of the total tree biomass, decomposition of large lateral roots and taproots following forest harvest and re-establishment potentially impact nutrient supply and carbon sequestration in pine systems over several decades. If the relationship between stump diameter and decomposition of taproot and lateral root material, i.e., wood and bark, can be quantified, a better understanding of rates and patterns of sequestration and nutrient release can also be developed. This study estimated decomposition rates from in-situ root systems using a chronosequence approach. Nine stands of 55- to 70-year-old loblolly pine (Pinus taeda L.) that had been clear-cut 0, 5, 10, 20, 25, 35, 45, 55, and 60 years ago were identified on well-drained Piedmont soils. Taproot and lateral root systems were excavated, measured, and weighed. Although more than 50% of the total root mass decomposed during the first 10 years after harvest, field excavations recovered portions of large lateral roots (>5 cm diameter) and taproots that persisted for more than 35 and 60 years, respectively. Results indicate that decomposition of total root biomass, and its component parts, from mature, clear-cut loblolly pine stands, can be modeled with good precision as a function of groundline stump diameter and years since harvest.

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