Micropropagation of Ulmus pumila L. from mature trees

The American Elm (Ulmus americana L.) has been plagued by Dutch Elm Disease (DED), a lethal disease caused by the fungus Ceratocystis ulmi (Buisman) c. Moreau. Since its initial appearance in North America around 1930, DED has wrought inexorable devastation on the American elm population, triggering both environmental and economic losses. In response to the havoc caused by the disease, many attempts have been made to hybridize U. americana with a few ornamentally less desirable, though highly DED resistant, Asian species (mainly the Siberian elm, Ulmus pumila L., and the Chinese elm Ulmus parvifolia Jacq.). The goal is to develop, through breeding efforts, hybrid progeny that display the ornamentally desirable characteristics of U. americana with the disease resistance of the Asian species. Unfortunately, however, all attempts to hybridize U. americana have been prevented by incompatibility. Only through a firm understanding of both compatibility and incompatibility will it be possible to circumvent the incompatibility and hence achieve hybridization.

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Monitoring natural stand change in the forest reserve of Liedekerke, Flanders (Belgium)

Silva Gandavensis ◽

10.21825/sg.v64i0.824 ◽

1999 ◽

Vol 64 ◽

Cited By ~ 1

Author(s):

D. Van den Meersschaut ◽

B. De Cuyper ◽

K. Vandekerkhove ◽

N. Lust

Keyword(s):

Species Composition ◽

Castanea Sativa ◽

Basal Area ◽

Alnus Glutinosa ◽

Indigenous Species ◽

Stem Number ◽

Mature Trees ◽

Forest Reserve ◽

Natural Stand ◽

Sweet Chestnut

Natural stand changes in the forest reserve of Liedekerke were analysed during the period 1986-1996, using a permanent grid of circular plots. The monitoring concentrated on natural changes in species composition, using stem number and basal area as indicators, and changes in spatial distribution and colonization capacities of trees and shrubs, with special interest in the competition between exotic and indigenous species. After only a decade of monitoring important natural changes in the woody layer were detected. The pioneer forest is gradually maturing through self-thinning processes and shifts in species composition. The overall stem number decreased with 33.6%, while the basal area increased with 20.9%. Birch (Betula pendula/ pubescens) and indigenous oak (Quercus robur/petraea) remained dominant. More tolerant exotic species, like red oak (Quercus rubra) and sweet chestnut (Castanea sativa), are slowly increasing their share in the species composition and expanding their range. Pioneer species on the other hand, like aspen (Populus tremula), willow (Salix capreaicinerealaurita), alder buckthorn (Frangula alnus) and common (Alnus glutinosa) and grey alder (A. incana), strongly declined. Black cherry (Prunus serotina) seems to be slowly invading the forest due to its massive natural regeneration. Strong competition may be expected especially from rowan ash (Sorbus aucuparia), which showed similar regeneration and colonization capacities. Elder (Sambucus nigra) dramatically extented its range, though its share remains marginal. Beech remained absent most probably due to the lack of mature trees in the vacinity of the forest. Finally this change detection allowed that general predictions could be made on the future natural development and composition of this forest reserve, which could serve forest management decisions.

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Micropropagation of Elaeagnus angustifolia from mature trees

Tree Physiology ◽

10.1093/treephys/15.10.691 ◽

1995 ◽

Vol 15 (10) ◽

pp. 691-693 ◽

Cited By ~ 7

Author(s):

J. M. Iriondo ◽

M. de la Iglesia ◽

C. Perez

Keyword(s):

Elaeagnus Angustifolia ◽

Mature Trees

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Infection by Phytophthora cinnamomi Rands of Roots of Eucalyptus calophylla R.Br. and Eucalyptus marginata Donn. ex Sm

Australian Journal of Botany ◽

10.1071/bt9770483 ◽

1977 ◽

Vol 25 (5) ◽

pp. 483 ◽

Cited By ~ 16

Author(s):

N Malajczuk ◽

AJ Mccomb ◽

CA Parker

Keyword(s):

Phytophthora Cinnamomi ◽

Light And Electron Microscopy ◽

Inhibitory Effect ◽

Lateritic Soil ◽

Root Damage ◽

Mature Trees ◽

Cortical Cells ◽

Eucalyptus Marginata ◽

Seedling Roots ◽

Loam Soil

On lateritic podzolic soils in Western Australia Eucalyptus calophylla is resistant to Phytophthora cinnamomi whereas Eucalyptus marginata is susceptible and eventually killed by the pathogen. On loam soils both eucalypts are resistant. Possible mechanisms for resistance of E. calophylla in lateritic soil and the inhibitory action of loam soils were investigated. Aseptically raised eucalypt seedlings succumbed to infection in liquid culture tubes. The mechanism of infection was compared by light and electron microscopy which showed similar fungal invasion and penetration into roots of both eucalypt species. Vegetative hyphae initially penetrated intercellularly and proliferated rapidly within cortical and stelar tissue. Intracellular invasion of these tissues occurred 48hr after initial infection through dissolution of the host cell wall. Chlamydospores were formed within a number of cortical cells. Unsuberized roots of mature trees produced aseptically showed reactions to invasion similar to those of the eucalypt seedling roots. Suberized roots were not invaded. The addition of small quantities of lateritic soil to sterile sand so as to introduce soil micro-organisms without altering the chemical and physical status of the sand, and subsequent inoculation of the sand with P.cinnamomi, resulted in a reduction of root damage on both eucalypts when compared with seedlings raised in sterile sand. Roots of E.calophylla were less severely damaged than those of E.marginata. The addition of small quantities of loam soil significantly reduced root damage in seedlings of both species. These results parallel both pot experiments and field observations, and suggest that microorganisms of the rhizosphere may be an important factor in the resistance of E.calophylla to infection, and in the inhibitory effect of loam soil on P.cinnamomi.

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Exploring the past of Mavrovouni forest in the Pindus Mountain range (Greece) using tree rings of Bosnian pines

Trees ◽

10.1007/s00468-021-02189-6 ◽

2021 ◽

Author(s):

Anastasia Christopoulou ◽

Nikolaos M. Fyllas ◽

Barbara Gmińska-Nowak ◽

Yasemin Özarslan ◽

Margarita Arianoutsou ◽

...

Keyword(s):

Fire History ◽

Ring Width ◽

Severe Drought ◽

Mountain Range ◽

Degree Days ◽

Mature Trees ◽

The Past ◽

Natural Agent ◽

Fire Ignition ◽

Animal Grazing

Abstract Key message Long Bosnian pine chronologies from different mountains are shaped by different climatic parameters and can help identify past drought events and reconstruct landscape histories. Abstract We developed a 735-year-long Pinus heldreichii chronology from the southern distribution limit of the species, expanding the available database of long Bosnian pine chronologies. Tree-ring growth was mainly positively correlated with growing degree days (GDD: r1950–2018 = 0.476) while higher temperatures during both winter and growing season also enhanced growth (TWT: r1950–2018 = 0.361 and TGS: 0.289, respectively). Annual precipitation, during both calendar and water years, had a negative but weaker impact on annual tree growth. The newly developed chronology correlates well with chronologies developed from the neighboring mountains. The years with ring width index (RWI) lower than the average were found to correspond to cool years with dry summers. Still, the newly developed chronology was able to capture severe drought events, such as those in 1660, 1687, and 1725. Several old living trees had internal scars presumably caused by fires. Therefore, old mature trees could be used for fire history reconstruction in addition to climate reconstruction. Although the presence of lightning scars indicates an important natural agent of fire ignition, human activities associated with animal grazing could also be an underlying reason for fires in the region.

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Effects of ontogenetic stage and leaf age on leaf functional traits and the relationships between traits in Pinus koraiensis

Journal of Forestry Research ◽

10.1007/s11676-021-01308-w ◽

2021 ◽

Author(s):

Meng Ji ◽

Guangze Jin ◽

Zhili Liu

Keyword(s):

Significant Positive Correlation ◽

Leaf Age ◽

Leaf Traits ◽

Ontogenetic Stage ◽

Pinus Koraiensis ◽

Mature Trees ◽

N Content ◽

Ontogenetic Stages ◽

Leaf N Content ◽

Leaf N

AbstractInvestigating the effects of ontogenetic stage and leaf age on leaf traits is important for understanding the utilization and distribution of resources in the process of plant growth. However, few studies have been conducted to show how traits and trait-trait relationships change across a range of ontogenetic stage and leaf age for evergreen coniferous species. We divided 67 Pinus koraiensis Sieb. et Zucc. of various sizes (0.3–100 cm diameter at breast height, DBH) into four ontogenetic stages, i.e., young trees, middle-aged trees, mature trees and over-mature trees, and measured the leaf mass per area (LMA), leaf dry matter content (LDMC), and mass-based leaf nitrogen content (N) and phosphorus content (P) of each leaf age group for each sampled tree. One-way analysis of variance (ANOVA) was used to describe the variation in leaf traits by ontogenetic stage and leaf age. The standardized major axis method was used to explore the effects of ontogenetic stage and leaf age on trait-trait relationships. We found that LMA and LDMC increased significantly and N and P decreased significantly with increases in the ontogenetic stage and leaf age. Most trait-trait relationships were consistent with the leaf economic spectrum (LES) at a global scale. Among them, leaf N content and LDMC showed a significant negative correlation, leaf N and P contents showed a significant positive correlation, and the absolute value of the slopes of the trait-trait relationships showed a gradually increasing trend with an increasing ontogenetic stage. LMA and LDMC showed a significant positive correlation, and the slopes of the trait-trait relationships showed a gradually decreasing trend with leaf age. Additionally, there were no significant relationships between leaf N content and LMA in most groups, which is contrary to the expectation of the LES. Overall, in the early ontogenetic stages and leaf ages, the leaf traits tend to be related to a "low investment-quick returns" resource strategy. In contrast, in the late ontogenetic stages and leaf ages, they tend to be related to a "high investment-slow returns" resource strategy. Our results reflect the optimal allocation of resources in Pinus koraiensis according to its functional needs during tree and leaf ontogeny.

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Occupancy of two forest specialist birds in the Southern Mistbelt Forests of KwaZulu-Natal and Eastern Cape, South Africa

Bird Conservation International ◽

10.1017/s0959270920000544 ◽

2020 ◽

pp. 1-16

Author(s):

S. THOBEKA GUMEDE ◽

DAVID A. EHLERS SMITH ◽

YVETTE C. EHLERS SMITH ◽

SAMUKELISIWE P. NGCOBO ◽

MBALENHLE T. SOSIBO ◽

...

Keyword(s):

South Africa ◽

Camera Trap ◽

Habitat Requirements ◽

Stem Density ◽

Grass Cover ◽

Eastern Cape ◽

Wet Season ◽

Mature Trees ◽

Natural Habitats ◽

Kwazulu Natal

Summary Establishing the specific habitat requirements of forest specialists in fragmented natural habitats is vital for their conservation. We used camera-trap surveys and microhabitat-scale covariates to assess the habitat requirements, probability of occupancy and detection of two terrestrial forest specialist species, the Orange Ground-thrush Geokichla gurneyi and the Lemon Dove Aplopelia larvata during the breeding and non-breeding seasons of 2018–2019 in selected Southern Mistbelt Forests of KwaZulu-Natal and the Eastern Cape, South Africa. A series of camera-trap surveys over 21 days were conducted in conjunction with surveys of microhabitat structural covariates. During the wet season, percentage of leaf litter cover, short grass cover, short herb cover, tall herb cover and saplings 0–2 m, stem density of trees 6–10 m and trees 16–20 m were significant structural covariates for influencing Lemon Dove occupancy. In the dry season, stem density of 2–5 m and 10–15 m trees, percentage tall herb cover, short herb cover and 0–2 m saplings were significant covariates influencing Lemon Dove occupancy. Stem density of trees 2–5 m and 11–15 m, percentage of short grass cover and short herb cover were important site covariates influencing Orange Ground-thrush occupancy in the wet season. Our study highlighted the importance of a diverse habitat structure for both forest species. A high density of tall/mature trees was an essential microhabitat covariate, particularly for sufficient cover and food for these ground-dwelling birds. Avian forest specialists play a vital role in providing ecosystem services perpetuating forest habitat functioning. Conservation of the natural heterogeneity of their habitat is integral to management plans to prevent the decline of such species.

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El Niño-Southern Oscillation affects the water relations of tree species in the Yucatan Peninsula, Mexico

Scientific Reports ◽

10.1038/s41598-021-89835-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jorge Palomo-Kumul ◽

Mirna Valdez-Hernández ◽

Gerald A. Islebe ◽

Manuel J. Cach-Pérez ◽

José Luis Andrade

Keyword(s):

Water Potential ◽

Leaf Area ◽

Tropical Forests ◽

Specific Leaf Area ◽

Tree Species ◽

Deciduous Species ◽

Mature Trees ◽

Seasonally Dry ◽

Seasonally Dry Tropical Forests ◽

Dry Tropical Forests

AbstractWe evaluated the effect of ENSO 2015/16 on the water relations of eight tree species in seasonally dry tropical forests of the Yucatan Peninsula, Mexico. The functional traits: wood density, relative water content in wood, xylem water potential and specific leaf area were recorded during the rainy season and compared in three consecutive years: 2015 (pre-ENSO conditions), 2016 (ENSO conditions) and 2017 (post-ENSO conditions). We analyzed tree size on the capacity to respond to water deficit, considering young and mature trees, and if this response is distinctive in species with different leaf patterns in seasonally dry tropical forests distributed along a precipitation gradient (700–1200 mm year−1). These traits showed a strong decrease in all species in response to water stress in 2016, mainly in the driest site. Deciduous species had lower wood density, higher predawn water potential and higher specific leaf area than evergreen species. In all cases, mature trees were more tolerant to drought. In the driest site, there was a significant reduction in water status, regardless of their leaf phenology, indicating that seasonally dry tropical forests are highly vulnerable to ENSO. Vulnerability of deciduous species is intensified in the driest areas and in the youngest trees.

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Post-fire survival and flushing in three Sierra Nevada conifers with high initial crown scorch

International Journal of Wildland Fire ◽

10.1071/wf08129 ◽

2009 ◽

Vol 18 (7) ◽

pp. 857 ◽

Cited By ~ 8

Author(s):

Chad T. Hanson ◽

Malcolm P. North

Keyword(s):

Sierra Nevada ◽

Pinus Ponderosa ◽

Fire Severity ◽

Conifer Species ◽

Mature Trees ◽

Salvage Logging ◽

Abies Magnifica ◽

Crown Scorch ◽

Tree Survival ◽

Large Trees

With growing debate over the impacts of post-fire salvage logging in conifer forests of the western USA, managers need accurate assessments of tree survival when significant proportions of the crown have been scorched. The accuracy of fire severity measurements will be affected if trees that initially appear to be fire-killed prove to be viable after longer observation. Our goal was to quantify the extent to which three common Sierra Nevada conifer species may ‘flush’ (produce new foliage in the year following a fire from scorched portions of the crown) and survive after fire, and to identify tree or burn characteristics associated with survival. We found that, among ponderosa pines (Pinus ponderosa Dougl. ex. Laws) and Jeffrey pines (Pinus jeffreyi Grev. & Balf) with 100% initial crown scorch (no green foliage following the fire), the majority of mature trees flushed, and survived. Red fir (Abies magnifica A. Murr.) with high crown scorch (mean = 90%) also flushed, and most large trees survived. Our results indicate that, if flushing is not taken into account, fire severity assessments will tend to overestimate mortality and post-fire salvage could remove many large trees that appear dead but are not.

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