Relationship of macrofungal population to silvicultural treatments in a recently harvested pine forest

Forest Ecology and Management, 31 (1990) 109-119

109

Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

Relationship of Macrofungal Population to Silvicultural T r e a t m e n t s in a Recently H a r v e s t e d P i n e Forest JOHN E. MAYFIELD 1, M. BOYD EDWARDS 2 and WILLIAM V. DASHEK 3

1Department of Biology, North Carolina Central University, Durham, NC 27707 (U.S.A.) 2USDA Forest Service, Southeastern Forest Experiment Station, Rte. 1, Box 182A, Dry Branch, GA 31020 (U.S.A.) 3Department of Biology, Atlanta University, Atlanta, GA 30314 (U.S.A.) (Accepted 27 January 1989)

ABSTRACT Mayfield, J.E., Edwards, M.B. and Dashek, W.V., 1990. Relationship of macrofungal population to silvicultural treatments in a recently harvested pine forest. For. Ecol. Manage., 31: 109-119. Both mechanical and chemical treatments of clear-cut pine forests have been shown to promote both growth and vigor in forest regeneration. Although the relationship between certain macrofungi and the forest ecosystem is well established, there is little information regarding the effects of silvicultural site-preparation treatments on the occurrence of these fungi. Randomly selected plots that received no (additional) treatment after clear-cutting [control (C) ] and plots that were sheared roller-chopped (SC), and chopped and herbicide-treated (CH) following clear-cutting were sampled for visible macrofungal fruiting bodies. Fifty-five fungal genera were collected from the entire study areas. There were 29, 41 and 32 species collected in C, SC and CH plots, respectively. Fifty percent of the fruiting-body biomass occurred within CH plots, while 30% and 17% occurred within SC and C plots, respectively. The degree of correlation between both site-preparation and fungal biomass varied according to species.

INTRODUCTION

Southern pines, of which loblolly pine (Pinus taeda) is the most plentiful, are important sources of the U.S.A.'s timber supply. Despite its rapid growth, loblolly pine production will not be able to meet the increased demands for its timber unless its generation is enhanced through either natural or artificial means. Attaining maximum biomass for a loblolly-pine forest may be approached by planting genetically improved seeds, controlling both infectious and noninfectious diseases, and maximizing nutrient utilization. Both disease susceptibility and the availability of soil nutrients are factors which can be altered 0378-1127/90/$03.50

© 1990 Elsevier Science Publishers B.V.

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during the early years of regeneration (Kowalski, 1982). Some type of site preparation (either mechanical, chemical or both) is necessary to obtain both relatively high growth-rate and vigor in the regenerating forest (Schultz, 1976). Although there are reports describing the advantages of site preparation in reforestation, few have dealt with the relationship of site preparation to soil micro-organisms. Fungi are important soil organisms in the forest ecosystem because they degrade forest litter and participate in the recycling of nutrients. To completely understand the mechanisms by which site preparation influences both the re-establishment and growth of a harvested forest, it is necessary to define the relationships between site-preparation treatments and fungal populations. The macrofungi (fungi producing highly conspicuous fruiting bodies) include members of both the Ascomycetes and Basidiomycetes. Their ability to concentrate large amounts of both nutrients and water within fruiting bodies (Vogt and Edmonds, 1980 ) render them important organisms within the forest population. Although fruiting-body biomass does not include the soil-borne hyphae, it does provide an indication of their occurrence (Vogt et al., 1981). Even though several techniques to isolate soil fungi exist, these methods may select only certain species because of the preferential germination of propagules (Harley, 1971; Watson et al., 1974). The purpose of this investigation was to determine whether the specific methods of site preparation affected those fungi commonly associated with either the stand or individual trees. This investigation appears to be the first report of an association between a fungal population and site-preparation treatments within a harvested loblolly-pine forest. METHODS

Location and preparation of sites The study area, located within the Hitchiti Experimental Forest near Juliette, Georgia, consisted of a 35-ha loblolly-pine site harvested in the winter of 1980. During the summer of 1981, six methods of mechanical site-preparation treatments were carried out (Edwards, 1983). Three of these site-preparation treatments, with three replicates each, were selected for study, as follows: clear-cut without any additional treatment [control (C)]; shear and roller-chop (SC); and chop and herbicide-application (CH) (Velpar Gridball applied by hand at 28 kg h a - 1). Three randomly selected plots of each treatment were employed, yielding a total of nine experimental plots. Each plot was a 20.0 X 40.5-m rectangle nested within an 0.81-ha treatment plot.

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Collection of fruiting bodies During the period February-June 1983, visible fungal fruiting bodies were collected along two 3.3-m wide {approximately 46 m long) transects which extended diagonally across the plot. One of the transects was discontinuous at the point where the other transect crossed, to avoid redundant sampling within the plot. Transects were divided into 17 sectors, each 5.5 X 3.3 m. The fruiting bodies collected within a sector were returned to the laboratory for identification. Fruiting bodies were identified to species whenever possible, with a representative of each species being photographed. All fruiting bodies of either a given genus or species were pooled according to the collection sector, and placed into pre-weighed aluminium containers for oven-drying to constant weight at 75°C.

Statistical analysis Certain of the data were analyzed with a one-way analysis of variance, utilizing a confidence level of P= 0.05 for statistical significance (Snedecor and Cochran, 1980). RESULTS

Identification of site fungi Table 1 lists the fruiting bodies gathered during different collections within each treatment. Fifty-five fungi were identified to genus, of which 41 were identified further to species. All the fungi were basidiomycetes, except Peziza badia, an ascomycete. There were 29, 41 and 32 species of fungal fruiting bodies collected from the C, SC and CH plots, respectively. Some of the fungi, such as Coriolus versicolor, Gloeophyllum sapiarium, Lenzites betulina, Hirschioporus abietinus, and SchizophyUum commune, were collected in all nine sample plots.

Dry-weight determination The presence of a fungus within a given plot may not reflect its frequency of occurrence if neither the biomass nor number of times the fruiting bodies were encountered within a plot were included. Therefore, dry-weight determinations of fruiting bodies were performed. Dry-weight data are reported for fruiting bodies of those fungi which occurred either in at least two replicates of each treatment or which made a substantial contribution to the total dry-weight (Table 2). Whereas 53% of the total fruiting-body dry-weight (12 400 g ha-1 )

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TABLE 1 Fungal fruiting bodies collected in the replicates of each treatment a Fungus

Treatment b C

Calocera cornea Clitocybe caespitosa Coriolus hirsutus Coriolus pubescens Coriolus versicolor Cortinarius Cortinarius coUinitos Dacromyces Entoloma Exida Ganoderma lucidum Geastrum Geastrum mammosus Geastrum saccatum Gloeophyllum sepiarium GloeophyUum striatum Gomphus floccosus Hirschioporus abietinus Hirschioporus pargamenus Hydnum Lenzites betulina Lycoperdon pyriforme Mycena Panus Perenniporia campacta Perenniporia tenuis Peziza badia Phaeolus schweinitzii

SC

Fungus CH

/ U

/ •

• •

# #

/ / U

/ / []

/ / I #

[J U

/ /

#

U

[] #

/

Phlebia radiata Phellinus heteromorpha PheUinus pini PheUinus rigida Phellinus Pholiota Polyporus adustus Polyporus arcularius Polyporus dependens Polyporus fimbratus Polyporus planellus Polyporus tulipiferae Polyporus velutinus Poronidulus conchi[er Pycnoporus cinnabar••us Schizophyllum commune Stereum Stereum gausapaptum Stereum hirsutum Stereum murraii Stereum sanguinolentum Steccherinum rhois Thelephora Tremella lutescens Tricholoma Tyromyces caesius Tyromyces spraguei

Treatment C

SC

CH

# # / /

• • /

• /

/ • /

/

• # # # /

/ / [] / / #

LA • • LA [] / =

/ = =

/ # # / • [] # LJ / LA

=

[A

/ = = # LA

/

aThe treatment plots were clear-cut without any additional treatment (C), shear and roller-chopped ( SC ), and chopped and herbicide-application (CH). bSymbols in the column represent the extent to which the fungi were observed within the treatment plots:/, I; = , II; lA, I I I ; # , Iⅈ [], I&III; V~, II&III; • , I&II&III.

was collected from the CH plot, 30% (7300 g ha -1) and 17% (3820 g ha -1) were derived from the SC and C sites, respectively. A significant increase in both the SC and CH plots compared to the C plots could be observed among fungi such as Lenzites betulina, Coriolus hirsutus, Stereum gausapatum, S. hirsutum and GloeophyUum striatum. Only in the cases of Phellinus heteromorpha, Phlebia radiata and Stereum were the greatest producers of biomass reported for the C plots. The difference between the total biomasses of fruiting bodies collected in SC

RELATIONSHIPOF MACROFUNGITO SILVICULTURALTREATMENTSIN A PINE FOREST

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TABLE 2 Dry-weight (g h a - ' ) of fruiting bodies collected in each site-preparation plot Fungus

Coriolus versicolor Lenzites betulina Coriolus pubescens Gloeophyllum sepiarium a Coriolus hirsutus ~ Phlebia radiata Hirschioporus abietinus Stereum gausaptum a Polyporus velutinus GloeophyUum striatum Polyporus arcularius Stereum SchizophyUum commune Lycoperdonpyriforme Hirschioporus pargamenus ~ Phellinus heteromorpha Tyromycescaesius Perenniporia compacts Stereum hirsutum Unidentified fungi Total dry-weight Percent of all treatments

Method of site preparation Clear-cut (Control)

Shear and rollerchopped

Chopped and herbicideapplication

1100 ± 45 b 84 ± 9 331 ± 23 430 ± 17 220 ± 29 411 ± 19 180 ± 15 62 ± 9

1830 +_31 1727 ± 34 265 ± 28 254 ± 18 542 ± 6 190 _+15 333 ± 21 161 ± 14

18 ± 6 25 ± 6 161± 13 87 ± 6 1 181 ± 11 95 ___12

164 ± 12 283 ± 17 89 ± 11 77 ± 5 96+_ 8 17 ± 5 26 ± 6 18± 4 45 ± 7 280 +_16 633 7030 30

7040 ± 86 1220 ± 33 576 ± 43 629 ± 29 464 +_20 214 ± 13 201 _+ 8 392 ± 19 513 ± 29 96 ± 12 31 ± 6 53 ± 8 133 ± 8 131 ± 15 398 ± 26 5± 3

49 +_ 9 385 3820 17

70 ± 10 82 +_12 152 12 400 53

aSignificant at P = 0 . 0 5 (one-way analysis of variance). bData are means and standard deviations, where n = 3. These data include replicates with 0 returns.

and CH plots may not be significant if Coriolus versicolor's dry-weight is substracted, whereas there is still a significant difference between the dry-weights from C and the other two site-preparation treatments. Seasonal variation Although this investigation's objectives did not include consideration of seasonal variations, the order in which plots were sampled was compared to determine if the results were more influenced by the time of their collection than site-preparation treatment (Table 3). Some fungi were collected in consecutively sampled plots rather than from plots of any specific treatment. For example, PheUinus pini was collected during the period 15-30 February from the second- and third-sampled plots, i.e., C and SC, respectively. Pholiota was

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TABLE

3

Mean dry-weight (g ha -1)

per sample plot for each treatment arranged according to sampling

order Fungus

Pholiota S t e r e u m murraii PheUinuspini Hirschioporuspargamenus Perenniporia compacta Polyporus tulipiferae Phellinus heteromorpha

Sample plot CH ~

Cc

SC d

C

SC

CH

SC

C

CH

I-2 b

I-3

I-4

II-3

II-4

II-5

III-4

III-5

III-6

25

11

6

13

7

26

1

-

-

-

14

718

-

-

-

1200

253

-

108

51

-

162

146

104

-

32

47

31

36

120

-

60

16

15

258

8

28

64

640

103

389

84

Stereumgausapatum Geastrum Stereum hirsutum Lycoperdon TremeUa lutescens GloeophyUum striatum Polyporus arcularius Tyromyces spraguei

Total d r y - w e i g h t aCH =

.

.

.

.

.

94 .

. -

-

7

535

-

-

13

-

-

31

-

. -

-

528

383

-

148

-

123

6

15

247

-

-

2

1

-

-

16

-

27

-

158

271

306

55

-

-

559

12

12

62

278

62

213

346

594

937

1347

463

. 2485

. 841

.

. 2138

. 234

.

247

Chopped and herbicide-application.

bI, I I , a n d I I I = C o l l e c t i o n s . cC -- C o n t r o l . dSC =

Shear and roller-chopped.

gathered from all three treatment groups but only during the first three collections. It is apparent that the occurrences of Stereum murraii, Tremella lutescens and Tyromyces spraguei were due to sampling time rather than the type of site-preparation treatment. Fruiting bodies of Geastrum and Phellinus heteromorpha appeared in all three treatment plots during the first three collections occurring in February, but appeared to be more treatment-specific after the second collection. Gloeophyllure striatum, never encountered within C plots, was observed within each of the other six plots except for one replicate of the CH treatment. There is no compelling evidence to suggest a correlation between site-preparation treatment and the presence of Perenniporia compacta, Polyporus tulipi[erae, S. guasapatum and S. murraii since their occurrences seemed to coincide more closely with collection time. However, there were instances in which fruiting-body occurrence was associated with collection time, while dry-weight data suggested a correlation between site-preparation treatment and biomass accumulation. For example, there was a decrease in Perreniporia compacta's dry-

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weight from the first through the last collection. The only instance of Perenniporia compacta's occurrence after the third collection was in the sixth sampling, which was a CH plot. The fruiting-body dry-weight for this plot was less than that of the three previously sampled plots. Even though the dry-weight value was reduced for fruiting bodies in the sixth collection (CH), the absence of observable fruiting bodies in the fourth and fifth plots may constitute limited evidence for a treatment-specific correlation. To determine whether there were fruiting bodies which were favored by any specific site-preparation method, fungi were sought that exhibited an appreciable increase in biomass for one treatment when compared to the other two. There were 4, 7, and 8 fungal species that produced a disproportionate biomass in C, SC, and CH plots, respectively. GloeophyUum sepiarium, Phellinus heteromorpha, Phlebia radiata and Stereum were the only fruiting bodies providing significant biomass in the C plots. Together, these fungi accounted for 1600 g h a - i , representing approximately 37% of the C plots total fruiting-bodies' biomass. Those fruiting bodies favored by the SC plots constituted 45 % (2810 g h a - 1) of the total dry-weight in these plots, while the CH-preferred fruiting bodies made up 74% (9180 g ha -1) of the plot's total. Most of the more-dominant fruiting bodies in SC plots, such as L. betulina, C. hirsutus, H. abietinus and Polyporus arcularius, were also collected in the other site-preparation-treatment plots while Tyromyces caesius, the sole exception, was collected only in SC. Without exception, all of the CH plots' dominant fruiting bodies were encountered in the other two treatment plots. The fruiting-body biomass of Perreniporia compacta and S. commune did not exhibit marked differences between the CH plots and those plots for which they registered the second-highest biomass. Most of the differences between plots with the highest and those with the next-highest biomass ranged from 1.3 to 2.0 times. There was only one instance in which there was a greater than three-fold difference between the plot having the highest biomass and the one with the next-highest: i.e. almost a 4.0-fold increase in the biomass of C. versicolor in the CH plot over the plot possessing the next-highest biomass value

(sc). Coriolus oersicolor was the most abundant fruiting body found within all treatment plots, accounting for about 26% of the biomass in both the C and SC plots and for approximately 57% of the biomass in the CH plot. The 15 100 g ha-1 obtained during the February (first sampling of CH plot) collection is almost a four-fold increase over the 3900 g ha -1 collected during April (the second sampling of a CH plot ), and a 7 -fold enhancement over the 2140 g h a - 1 obtained during the final collection in May. It was apparent that the occurrence of C. versicolor fruiting bodies was sensitive to both seasonal variations and the method of site preparation.

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DISCUSSION The occurrences of 53, 30 and 17% of the fruiting biomass in the CH sites, SC sites and C sites, respectively, indicate that the method of site preparation influences macrofungal biomass production. The C site was considered the site-preparation treatment of the least intensity, while the CH plot represented the most intensely affected site. The major difference between SC and CH is that the former involved only mechanical treatment whereas the latter is a combination of both mechanical and chemical treatments. The biomass increase - using the biomass data for C sites as base line values - for the SC treatment may be attributed to the size-range of residual wood, which has been shown to play a vital role in forest soil conditions (Harvey et al., 1981 ). Abbott and Crossley (1982) have suggested that the wood-decay rates can be influenced by the diameter of branch material. Since most of the fungi collected from the different sites were the wood-decay type, it is reasonable to relate the increased biomass in SC sites to an enhancement in wood-degradation activity. Any increase in this activity could be due to the size reduction of the wood pieces resulting from the roller blade. The observation that the greatest biomass production occurred within the sites receiving herbicide application together with chopping cannot be explained simply: although the growth of mycorrhizal fungi may be influenced by herbicides (Ogawa and Yambe, 1980; Trappe, 1983), there seems to be either little or no reported evidence that macro fungi are directly affected by herbicides. The rise in fruiting-body biomass could be due to an indirect effect resulting from the reduced population of some of the herbaceous plants on the site. Some of the fruiting bodies exhibit a marked capacity to both accumulate and store nutrients such as N, K, Ca, P and Mn (Stark, 1972; Vogt et al., 1981 ). The elevated quantities of biomass in CH sites may be due to the increased availability of rate-limiting nutrients in the herbaceous-plant-sparse soil. Since the occurrence of certain macro fungi is correlated with wood decay, it is also possible that the growth-stimulation factor may be the effect of herbicides on either the decay activity or the conditions of the residual wood. Even though the CH plots gave biomass yields about 3.0 and 1.8 times those of C and SC plots separately, these values were not paralleled by individual species as there were variations from species to species. This is to be expected, since some of these fungi have been shown to be quite different in their abilities to concentrate nutrients (Cromack et al., 1975 ) and their capacities to respond to various environmental conditions (Vogt and Edmonds, 1980). Since collections were performed only from February through June, the full effects of seasonal variations could not be assessed. In addition to seasonal variations, there were also weather conditions which may have exerted differential effects upon fruiting-body development (Lowe and Gilbertson, 1961). It was quite obvious that the occurrence of Hirschioporus pargamenus and Per-

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reniporia compacta's fruiting bodies was seasonally related, while the occurrence of Stereum gausapatum's appeared to be not only seasonal but also CHplot-preferred. The occurrence of macrofungal species has been attributed to seasonal succession (Visser and Parkinson, 1975; Joshi and Chauhan, 1982), forest ecosystem habitats (Rayner and Todd, 1977; Pop, 1981; Bisht and Harsh, 1983) intra- and interspecific antagonism (Keyes, 1968) and wildlife manipulation (Cushwa et al., 1970; Maser et al., 1978). All of the above could be factors in several of the species, such as G. sepiarium, C. hirsutus, S. gausapaturn and H. pargamenus, which displayed dry-weight differences which were significant at P= 0.05. The lack of statistically significant differences between treatments with some of the other species may be due to additional factors influencing fruiting-body development. Since most of the species were associated with wood, both the amount and depth of residual wood in the soil could have influenced the presence of specific fruiting bodies upon a given site. The species producing most biomass was C. versicolor, a ubiquitous species within forest ecosystems (Pop, 1981; Boddy and Rayner, 1983). The startling difference between the CH treatment and the other two treatments suggests both a pleomorphic nature of the fungus and a marked ability to take up both nutrients and water. For example, the February collection of fruiting bodies from the CH site resulted in a very high biomass as compared to that for the second and third CH replicates. This extremely high biomass accumulation in February may reflect the soil's high water-content during that period. Coriolus versicolor, accounting for approximately 42% of the total biomass for all plots, therefore requires serious consideration in the interpretation of the results of this investigation as well as to the effects of site-preparation treatment. Coriolus versicolor is one of the most important degraders of the complex polymers of which wood is comprised (Evans and Palmer, 1983). It is ubiquitous, as indicated by its abundance and frequencies of occurrences in population studies (Cowling and Merrill, 1966). The consideration of residual wood on a harvested forest site and the conditions necessary to regulate the activity of a decay fungus such as C. versicolor can be highly important information in forest management. Coriolus versicolormay serve as a nutrient repository on those sites treated with herbicides, releasing these accumulated nutrients through fruiting-body decay as young pine seedlings develop. Both residual wood and controlled wood-decay could be important to silvicultural practices. ACKNOWLEDGEMENTS We thank Dr. David Porter for identifying some of the fungi, and Mrs. Ruby Wright, Mrs. Joyce Lockhart and Mrs. Barbara Mercer for their clerical assistance.

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