Chemical Traits that Predict Susceptibility of Pinus radiata to Marsupial Bark Stripping

Bark stripping by mammals is a major problem for conifer forestry worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials. As a sustainable management option, we explored the extent to which natural variation in the susceptibility of P. radiata is under genetic control and is thus amenable to genetic improvement. Bark stripping was assessed at ages four and five years in two sister trials comprising 101 and 138 open-pollinated half-sib families. A third younger trial comprising 74 full-sib control-pollinated families was assessed at two and three years after planting. Significant additive genetic variation in bark stripping was demonstrated in all trials, with narrow-sense heritability estimates between 0.06 and 0.14. Within sites, the amount of additive genetic variation detected increased with the level of bark stripping. When strongly expressed across the two sister trials, the genetic signal was stable (i.e., there was little genotype × environment interaction). No significant non-additive effect (specific combining ability effect) on bark stripping was detected in the full-sib family trial, where it was estimated that up to 22.1% reduction in bark stripping might be achieved by selecting 20% of the less susceptible families. Physical traits that were genetically correlated, and likely influenced the amount of bark removed from the trees by the marsupials, appeared to depend upon tree age. In the older trials, these traits included bark features (presence of rough bark, rough bark height, and bark thickness), whereas in the younger trial where rough bark was not developed, it was the presence of obstructive branches or needles on the stem. In the younger trial, a positive genetic correlation between prior height and bark stripping was detected, suggesting that initially faster growing trees exhibit more bark stripping than slower growing trees but later develop rough bark faster and became less susceptible. While the presence of unexplained genetic variation after accounting for these physical factors suggests that other explanatory plant traits may be involved, such as chemical traits, overall the results indicate that selection for reduced susceptibility is possible, with potential genetic gains for deployment and breeding.

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Pine needle consumption and bark stripping by sheep grazing annual pastures in young stands of widely spaced Pinus radiata and P. pinaster

Agroforestry Systems ◽

10.1007/bf00045737 ◽

1985 ◽

Vol 3 (1) ◽

pp. 37-45 ◽

Cited By ~ 9

Author(s):

G. W. Anderson ◽

M. Hawke ◽

R. W. Moore

Keyword(s):

Pinus Radiata ◽

Sheep Grazing ◽

Pine Needle ◽

Bark Stripping

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Analysis of the transcriptome of the needles and bark of Pinus radiata induced by bark stripping and methyl jasmonate

BMC Genomics ◽

10.1186/s12864-021-08231-8 ◽

2022 ◽

Vol 23 (1) ◽

Author(s):

J. S. Nantongo ◽

B. M. Potts ◽

T. Frickey ◽

E. Telfer ◽

H. Dungey ◽

...

Keyword(s):

Methyl Jasmonate ◽

Secondary Metabolism ◽

Differential Expression ◽

Pinus Radiata ◽

Plant Responses ◽

Primary Metabolism ◽

Bark Stripping ◽

Transcriptional Responses ◽

Down Regulation ◽

Chemical Defences

Abstract Background Plants are attacked by diverse insect and mammalian herbivores and respond with different physical and chemical defences. Transcriptional changes underlie these phenotypic changes. Simulated herbivory has been used to study the transcriptional and other early regulation events of these plant responses. In this study, constitutive and induced transcriptional responses to artificial bark stripping are compared in the needles and the bark of Pinus radiata to the responses from application of the plant stressor, methyl jasmonate. The time progression of the responses was assessed over a 4-week period. Results Of the 6312 unique transcripts studied, 86.6% were differentially expressed between the needles and the bark prior to treatment. The most abundant constitutive transcripts were related to defence and photosynthesis and their expression did not differ between the needles and the bark. While no differential expression of transcripts were detected in the needles following bark stripping, in the bark this treatment caused an up-regulation and down-regulation of genes associated with primary and secondary metabolism. Methyl jasmonate treatment caused differential expression of transcripts in both the bark and the needles, with individual genes related to primary metabolism more responsive than those associated with secondary metabolism. The up-regulation of genes related to sugar break-down and the repression of genes related with photosynthesis, following both treatments was consistent with the strong down-regulation of sugars that has been observed in the same population. Relative to the control, the treatments caused a differential expression of genes involved in signalling, photosynthesis, carbohydrate and lipid metabolism as well as defence and water stress. However, non-overlapping transcripts were detected between the needles and the bark, between treatments and at different times of assessment. Methyl jasmonate induced more transcriptional responses in the bark than bark stripping, although the peak of expression following both treatments was detected 7 days post treatment application. The effects of bark stripping were localised, and no systemic changes were detected in the needles. Conclusion There are constitutive and induced differences in the needle and bark transcriptome of Pinus radiata. Some expression responses to bark stripping may differ from other biotic and abiotic stresses, which contributes to the understanding of plant molecular responses to diverse stresses. Whether the gene expression changes are heritable and how they differ between resistant and susceptible families identified in earlier studies needs further investigation.

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Ease of Access to An Alternative Food Source Enables Wallabies to Strip Bark in Tasmanian Pinus radiata Plantations

Forests ◽

10.3390/f11040387 ◽

2020 ◽

Vol 11 (4) ◽

pp. 387 ◽

Cited By ~ 1

Author(s):

Anna H. Smith ◽

David A. Ratkowsky ◽

Timothy J. Wardlaw ◽

Caroline L. Mohammed

Keyword(s):

Pinus Radiata ◽

Food Source ◽

Floristic Composition ◽

Radiata Pine ◽

Early Summer ◽

Bark Stripping ◽

Site Factors ◽

Generalist Herbivore ◽

The Difference ◽

Main Food Source

Bark stripping by the Bennett’s wallaby (Macropus rufogriseus (Desmarest) subsp. rufogriseus) from the lower stems of 3–6-year-old radiata pine (Pinus radiata D. Don) causes significant damage in Tasmanian plantations. The usual diet of this generalist herbivore is mainly grasses and broadleaved forbs. As the factors that attract a wallaby to supplement its diet by eating the bark of plantation pine trees are currently not elucidated, the present study aimed to determine how the incidence and severity of bark damage in 12 Tasmanian radiata pine plantations was influenced by various inter-site factors such as the floristic composition of the surrounding forest, and by various intra-site factors such as the height and circumference of individual trees, the number of branches in the first two whorls at the base of the tree, and their internode lengths. It was found that the greater the percentages of bare ground, bracken, and moss present in the five plots at each site, and the greater the percentage of grass, the wallaby’s main food source, the greater the likelihood of bark stripping. The difference between the mean minimum soil and air temperatures in spring, a driving force for carbohydrate production that occurs with tree growth in spring or early summer, was the only meteorological observation at the sites that was found to be significantly related to the extent of bark stripping.

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Ease of Access to an Alternative Food Source Enables Wallabies to Strip Bark in Tasmanian Pinus Radiata Plantations

10.20944/preprints202002.0169.v1 ◽

2020 ◽

Author(s):

Anna Smith ◽

David Ratkowsky ◽

Timothy Wardlaw ◽

Caroline Mohammed

Keyword(s):

Tree Growth ◽

Pinus Radiata ◽

Food Source ◽

Floristic Composition ◽

Radiata Pine ◽

Early Summer ◽

Bark Stripping ◽

Site Factors ◽

Generalist Herbivore ◽

Ease Of Access

Bark stripping by the Bennett’s wallaby (Macropus rufogriseus rufogriseus) from the lower stems of 3–6-year-old radiata pine (Pinus radiata) causes significant damage in Tasmanian plantations. The usual diet of this generalist herbivore is mainly grasses and broadleaved forbs. As the factors that attract wallabies to supplement its diet by eating the bark of plantation pine trees are currently not elucidated, the present study aimed to determine how the incidence and severity of bark damage in 12 Tasmanian radiata pine plantations was influenced by various inter-site factors such as the floristic composition of the surrounding forest and by various intra-site factors such as the height and circumference of individual trees, the number of branches in the first two whorls at the base of the tree, and their internode lengths. Site differences in the observed percentage of bark stripping were found to be related to ‘ease of access’ variables such as bare ground, bracken, and moss, ‘hindrance to access’ variables such as rock and woody debris, and the percentage of grass, the wallaby’s main food source, present in the five plots at each site. The difference between the mean minimum soil and air temperatures in spring, a driving force for carbohydrate production that occurs with tree growth in spring or early summer, was the only meteorological observation at the sites that was found to be statistically significant. Nevertheless, there was no direct evidence that it was the movement of sugars in the phloem tissue accompanying tree growth which provided wallabies with a supplementary food source.

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Seasonal dynamics in understorey abundance and carbohydrate concentration in relation to browsing and bark stripping of Tasmanian Pinus radiata plantations

Forest Ecology and Management ◽

10.1016/j.foreco.2013.02.002 ◽

2013 ◽

Vol 296 ◽

pp. 98-107 ◽

Cited By ~ 3

Author(s):

David E. Page ◽

Dugald Close ◽

Christopher L. Beadle ◽

Timothy J. Wardlaw ◽

Caroline L. Mohammed

Keyword(s):

Pinus Radiata ◽

Seasonal Dynamics ◽

Bark Stripping ◽

Carbohydrate Concentration

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Agroforestry in Eastern Otago: results from two long-term experiments

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.2000.62.2398 ◽

2000 ◽

pp. 93-98

Author(s):

G.G. Cossens ◽

M.F. Hawke

Keyword(s):

Soil Ph ◽

Tree Growth ◽

Pinus Radiata ◽

Carrying Capacity ◽

Livestock Grazing ◽

Tree Age ◽

Rapid Decline ◽

Pasture Production ◽

Clover Content ◽

Pasture Yield

During the first 20 years of a Pinus radiata tree rotation, tree growth and pasture yield were assessed under a range of tree spacings at Invermay and Akatore, two coastal sites in Eastern Otago. Pasture yield in association with trees thinned to 100 stems per hectare (sph) was comparable to that from open pasture up to a tree age of 12 years. By the 19th year, however, pasture production declined to 63% of open pasture yield at Invermay and to 42% at Akatore. At 200 and 400 sph at Akatore, pasture yield was similar to that from open pasture at tree age 12 years but declined to 27% and 0% of open pasture yield respectively by year 20. At both Invermay and Akatore, the ryegrass and clover content of open pasture was relatively constant throughout the term of the trial. However, both the ryegrass and clover content of pasture beneath trees began to decline by tree age 12 years with a very rapid decline at Akatore in the number of pasture species at 200 sph by the 19th year. No pasture remained at 400 sph, after 19 years. Livestock carrying capacity with sheep on tree treatments at Invermay decreased from 100% of open pasture at year 6 to 60% by year 10. At Akatore, livestock carrying capacity averaged over the 20-year life of the trial was 4.1 stock units per hectare with a maximum of 8.1 stock units at a tree age of 8 years. Tree growth at both sites was similar, averaging between 1 and 1.1 m/year in height over 20 years, with trees at Invermay at 100 sph averaging 9% greater height and diameter growth than at Akatore. Increasing tree stocking from 100 to 200 to 400 sph at Akatore, resulted in increased tree height, but decreased diameter at breast height. A comparison of the East Otago trees with those in a similar trial at Tikitere (Rotorua) 900 km further north indicated that the southern trees were about 6 years later in their growth pattern by tree age 20 years. On both sites, soil pH tended to be lower in the presence of trees and was significantly lower than in open pasture by year 20. The results and comparisons with the Tikitere data suggest that, in an integrated agroforestry regime, there will be livestock grazing under the trees further into the tree rotation in Otago than in North Island sites. However, slower tree growth would result in a longer rotation time to harvest. Current recommendations to farmers are to plant trees on the less productive areas of the farm and adopt a tree stocking rate which fully utilises the site. Keywords: agroforestry, livestock, pasture, Pinus radiata, soil pH, tree stocking

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Adaptive Management Lessons for Serianthes nelsonii Conservation

Horticulturae ◽

10.3390/horticulturae7030043 ◽

2021 ◽

Vol 7 (3) ◽

pp. 43

Author(s):

Thomas E. Marler ◽

Cameron Musser ◽

April N. J. Cascasan ◽

Gil N. Cruz ◽

Benjamin E. Deloso

Keyword(s):

Root Zone ◽

Adventitious Root Formation ◽

Endangered Tree ◽

Rapid Decomposition ◽

Tree Population ◽

Sapling Growth ◽

Air Layers ◽

Sowing Seed ◽

Chemical Traits

The literature covering the biology, ecology, horticulture, and conservation of the critically endangered tree Serianthes nelsonii Merr. was reviewed. The roots, stems, and leaves of this charismatic legume tree revealed highly plastic traits and responded positively to horticultural manipulations to improve the quality of container-grown transplants. Pre-sowing seed treatments of seed coat scarification and 1 h of imbibition generated 85% to 90% germination at a temperature optimum of 26 °C. Adventitious root formation on air layers and successful unions on approach grafts were 100%. Seedling and sapling growth was maximum under 25% to 50% sunlight transmission, limited irrigation to ensure adequate root zone aeration, repetitive stem tip pruning to increase root:shoot quotient, and thigmic stress to retain an orthotropic orientation of stems. In situ regeneration on Guam was substantial but recruitment from seedling to sapling was nil. High quality leaf litter chemistry enabled rapid decomposition, and soils beneath the tree exhibited unique chemical traits that increased ecosystem health by creating spatial heterogeneity. The greatest unanswered questions focus on plant mortality. Research is needed to determine the reasons for the mortality of in situ seedlings, mortality within transplantation projects on Guam, and the mortality of 60% of the mature in situ tree population during the 26-year implementation of the national recovery plan. Horticultural researchers are ideally positioned to answer these urgent questions.

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