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Comparison of Acorn Production and Damage on Sites with Abundant and with Sparse Oak Regeneration
 


Comparison of Acorn Production and Damage on Sites with Abundant and with Sparse Oak Regeneration, [Cover]
D. H. Ramsey Library, Special Collections, UNC at Asheville 28804
Title Comparison of Acorn Production and Damage on Sites with Abundant and with Sparse Oak Regeneration
Alt. Title Comparison of Acorn Production and Damage on Sites with Abundant and with Sparse Oak Regeneration: Current Report 36 June 1962
Identifier  
Creator West Virginia University Agricultural Experiment Station
Subject Keyword U.S. Forest Service ; Western North Carolina ; 
Subject LCSH U.S. Forest Service
E.H. Tryon
K.L. Carvell
Date digital 2011-11-29
Publisher West Virgina University Agricultural Experiment Station
Contributor

E.H. Tryon, K.L. Carvell

Type booklet
Format [digital] image/jpeg/text ;
Source  
Language English
Relation  
Coverage temporal June 1962
Coverage spatial  
Rights Any display, publication or public use must credit D. H. Ramsey Library, Special Collections, University of North Carolina at Asheville.
Copyright retained by the authors of certain items in the collection, or their descendants, as stipulated by United States copyright law.
Donor  
Description An 8-page booklet about acorn production with tables and photographs
Acquisition  
Citation  D. H. Ramsey Library, Special Collections, University of North Carolina at Asheville 28804
Processed by Special Collections staff,  2011
Last update 2011-11-29
   
 Item I.D. # Page Description Thumbnail
 acorn
_0001
cover Comparison of Acorn Production and Damage on Sites with Abundant and with Sparse Oak Regenderation

 

CURRENT REPORT 36
JUNE 1962

West Virginia University Agriculture Experiment Station

acorn_0001.jpg (1034021 bytes)
0002 inside front cover THE AUTHORS

E. H. Tryon is Professor of Silviculture and Silviculturist. K. L. Carvell is Associate Professor of Silviculture and Associate Silviculturist.

The Cover

Seed traps are used to help determine the number of acorns produced and the damage from various causes.

Acknowledgment

Photographs showing acorn damage are courtesy of C. K. Dorsey, Professor of Entomology and Entomologist.

west virginia university agricultural experiment station

college of agriculture, forestry, and home economics A. H. vanlandingham, director

MORGANTOWN

 

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0003 3 Comparison of Acorn Production and Damage on Sites with Abundant and with Sparse Oak Regeneration

E. H. TRYON and K. L. CARVELL

A study of site factors which affect the amount of oak regeneration under mature oak stands is in progress, and is being conducted by foresters and entomologists of the West Virginia Agricultural Experiment Station. Site factors being studied are those within the four main groups—topographic, biotic, edaphic, and climatic—which are considered or found to have an important direct effect on the acorn, its germination, and establishment and juvenile growth of the oak seedling. Valuable information is being gained by this study concerning the conditions needed for the natural regeneration of oak stands. With the accumulation and application of such information, better silvicultural practices will be used in the management of oak forests.

The main purpose of this report is to present the results of a study of agents affecting acorns collected from oak stands under which abundant reproduction occurs, and from oak stands beneath which sparse reproduction occurs. An earlier publication1 indicated that little difference in acorn production occurred between the two conditions. However, the more intensive study reported here is based on a longer period of time, and it treats the importance of the individual agents affecting acorns on each of the two conditions where abundant and where sparse oak regeneration occur.

Plot Establishment

Seven paired areas supporting mature oak stands were selected for the study. The two portions of each paired area were as similar as could be found from the standpoint of elevation, topography, and stand composition and age. However, one portion of each pair had abundant oak reproduction, whereas on the other, reproduction was sparse. Two large oaks, one northern red (Quercus rubra L.) and one white (Quercus alba L.), were selected as plot trees on each portion of the paired area. Thus, four plot trees were on each of the seven paired areas, making a total of 28 plots.

'Tryon, B. H. and K. L. Carvell. 1958. Regeneration Under Oak Stands. West Virginia University Agricultural Experiment Station Bulletin 424T. 22 pp.

 

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0004 4 Two quarter-milacre seed traps and two quarter-milacre ground quadrats were established on the ground within the horizontal projection of the crown of each of the 28 oaks from which acorns were collected. Collections were made in the fall and spring during a five-year period, from 1954 to 1958 inclusive. By examination of the acorns, the total number of acorns and the amount of damage to and loss of acorns by destructive agents were computed.2 To test differences statistically, the count data were transformed by Vx+1, and the percentage data by the arcsin transformation for more efficient testing.

Results

The amount of oak reproduction, stems less than 0.5 inches d.b.h., differed greatly between the two portions of the paired areas. The sites with abundant oak reproduction had approximately five times as much as the sites with sparse oak reproduction, the former averaging 13,490 oak seedlings per acre as compared with only 2,615 oak seedlings per acre on the latter sites. This difference in amount of regeneration between the two situations is significant at the 1 per cent level.

A comparison of total acorn production and types of damage for areas with abundant and with sparse oak reproduction is presented in Table 1. For the conditions listed, none of the differences between numbers of acorns on the areas with abundant and with sparse oak reproduction is statistically significant. Although a somewhat larger number of acorns was produced on the sites with sparse oak reproduction, more sound acorns were produced when the reproduction was abundant. The differences however, were not large and, as indicated above, not significant. Also, a tendency existed for both insect and animal damage to acorns to be slightly higher on the areas where the sparse reproduction occurred.

In order to compare the condition of the acorns, especially damage on the two sites on the basis of equal acorn numbers, the sound and damaged acorns also are presented as a percentage of the total number produced on each site (Table 1). Again, none of the differences in percentage of acorns between the two sites for any condition is statistically significant. However, the trend for a higher proportion of sound acorns on the sites with abundant oak reproduction may again be observed, as well as the tendency for greater animal and insect damage on the sites with sparse oak regeneration.

Thus, neither the amount of animal nor insect damage to acorns differ appreciably between the sites with abundant oak regeneration and those with sparse oak regeneration.

2A more detailed account of the method is presented in West Virginia University Agricultural Experiment Station Bulletin 466T by E. H. Tryon and K. L. Carvell entitled Acorn Production and Damage. 18 pp. 1962.

 

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0005 5 A—A healthy acorn. The solid, fleshy portion filling the shell Is made up of the cotyledons.

B—This acorn has been completely destroyed by the acorn weevil larvae.

C—This acorn has been destroyed by the acorn caterpillar.

Heavy damage to the acorn crops by insects and animals is indicated. On each of the two sites, over 80 per cent of the acorns were damaged by these agents.

table 1. condition of acorns by numbers per mii.acre and percentage on sites with abundant and with sparse oak reproduction

(5-YEAR basis)

acokn condition NUMBKR pkrckntac.k
abundant oak reproduction spars k oak rkproduction abundant oak kkproiiuction sparse oak rkphoduction
108 190 312 159

40 113 5

71 246 SM

241 32 123 3

Per Cinl 17.6 30.9 50.8 25.9 fi.6 18.3 0.5 Per Cent 10.0 34.2 55.4 33.7 4.5 17.2 0.4
Cut, on ground ......
Missing from ground ........ Missing from tree ............ Other
615 710 100.0 100.0

 

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0006 6 Conclusions

Relatively small differences were found between sites with abundant oak reproduction and sites with sparse oak reproduction in: (1) total acorn production, (2) number of sound acorns produced, (3) damage to acorns by insects, and (4) damage to and loss of acorns by animals. The sites with abundant oak reproduction had nearly five times as many oak seedlings as those with sparse oak reproduction (13,490 oak seedlings per acre to 2,615). Therefore, acorn production and damage to the acorns by all or any single damaging agent were not primarily responsible for differences in amount of oak reproduction between the two situations studied.

Site factors affecting seedlings establishment, from the time of acorn germination through the juvenile growth period, are considered to be more important in determining the amount of oak reproduction than those factors directly affecting the acorn. Jn general, it is believed that the ability of oak regeneration to persist on a specific site is more closely related to environmental conditions than is its ability to become established.3 The environmental factors favoring oak regeneration beneath mature oak stands include increased sunlight resulting from past light logging operations, and reduced competition on the forest floor resulting from past fires and gra/ing, and also dry sites where stands tend to be open.

Although regular and abundant acorn crops are usually necessary to establish large numbers of oak seedlings, only through favorable environmental conditions can each wave of seedlings persist on the site to build up the advanced reproduction which will assure satisfactory species composition in the next rotation. On certain sites these conditions may exist without the aid of silvicultural treatment; however, on other areas an adjustment of conditions on the forest floor will be necessary during the decade prior to the regeneration period.

 

 

3Carvell, K. L. and E. H. Tryon. 1961. The Effect of Environmental Factors on the Abundance of Oak Regeneration Beneath Mature Oak Stands. Forest Science 7 :98-105.

 

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 0007 7 Animals cause heavy damage and loss of acorns. Damaged acorns often give clues as to the animal causing the damage. The acorns in (A) were damaged by gray squirrels, and those in (B) were damaged by the white footed mouse.  acorn_0007.jpg (666567 bytes)