Search

The detection of invasive species is a crucial step for environmental management. However, traditional methods often require intensive labor in the field, which tends to be time-consuming and costly. In contrast, drones can cover large areas quickly and efficiently, creating a cost-effective alternative. However, the use of drones to detect or monitor invasive trees in coastal ecosystems is still unusual. For this reason, we carried out a trial to verify whether drones can effectively detect invasive alien pine trees at reduced costs in comparison with traditional detection methods. A drone was used to survey an area invaded by pines in an open coastal ecosystem in southern Brazil. We estimated total cost and time for detecting and controlling pines with and without the use of a drone. When using a drone to locate pines and conduct targeted control activities, the cost was reduced to approximately one-third compared with traditional methods. The time needed to detect and control invasive trees was more than seven times less compared with traditional active search and control. Our study demonstrates the potential of drone use for early detection, monitoring and control of invasive plant species in coastal and other open ecosystems. The use of drones can provide a cost-effective and efficient way to detect invasive plant species, allowing for targeted control actions. [ABSTRACT FROM AUTHOR]

Pinewood nematode, Bursaphelenchus xylophilus, is one of the greatest threats to pine trees and is spreading all over the world. During the nematode's pathogenesis, plant microorganisms play important roles. However, many microbial communities, such as that in Pinus massoniana, a major host of B. xylophilus that is widely distributed in China, are not well studied, especially the fungal communities. Here, the endophytic and rhizospheric bacterial and fungal communities associated with healthy and B. xylophilus–infected P. massoniana were analyzed. The results showed that 7639 bacterial and 3108 fungal OTUs were annotated from samples of P. massoniana, the rhizosphere, and B. xylophilus. There were significant diversity differences of endophytic microbes between healthy and infected P. massoniana. The abundances of endophytic bacteria Paenibacillus, unidentified_Burkholderiaceae, Serratia, Erwinia, and Pseudoxanthomonas and fungi Penicillifer, Zygoascus, Kirschsteiniothelia, Cyberlindnera, and Sporothrix in infected pines were greater than those in healthy pines, suggesting an association of particular microbial abundances with the pathogenesis of B. xylophilus in pines. Meanwhile, the abundances of microbes of unidentified_Burkholderiaceae, Saitozyma, and Pestalotiopsis were greater and Acidothermus and Trichoderma were lower in the rhizosphere under infected pines than those under healthy pines and the differences might be caused by B. xylophilus–induced weakening of the health of pines. Our study explored the endophytic and rhizospheric microbial community changes potentially caused by B. xylophilus infection of pines. [ABSTRACT FROM AUTHOR]

Copyright of Fire Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Invasive trees can cause catastrophic reductions in diversity in invaded grasslands and savannas. Such reductions often appear to be particularly severe in the new biogeographic ranges of these invaders. We present results of a field study that examined the effect of slash pine (Pinus elliottii), native to the southeastern US, on savanna groundcover vegetation in the state of São Paulo in Brazil (cerrado) and in its native range in Mississippi (USA) following fire exclusion. We compared the difference in several community attributes between slash pine understories and adjacent open area in both São Paulo and Mississippi, and compared the effects of needle litter on native species in both continents. Slash pine was correlated with lower non-graminoid species richness and plant density in both São Paulo and Mississippi; however, these apparent negative effects were 4.6 and 11 times stronger in the non-native range of Brazil (for richness and density, respectively). Native graminoids were not present in invaded cerrado. Overhead slash pine canopy cover, pine density, and needle depth were 5.2, 3.7, and at 14 times higher, respectively, in Brazil than in Mississippi savannas, for similarly-aged pine stands. One year after implementing needle litter treatments in Brazilian cerrado and restored Mississippi savanna, plant density and non-graminoid species richness were highly suppressed, but to similar degrees in both ranges. Our results suggest that higher rates of needle deposition, associated with higher tree densities, contribute to the stronger suppression of native species in Brazil than in Mississippi. [ABSTRACT FROM AUTHOR]

Glyphosate is the herbicide most extensively used for site preparation and conifer release. It is a broad-spectrum herbicide and therefore crop safety is a critical issue. This study assessed the early effects of 14 different treatments, including no weed control, manual weed control, and 12 foliar-applied herbicide treatments at low, intermediate, high, and highest application rates and application timing on glyphosate phytotoxicity of containerized seedlings of Austrian pine (Pinus nigra J.F. Arnold.), Scots pine (P. sylvestris L.) and maritime pine (P. pinaster Aiton), conifer species widely used for afforestation and supplementary plantings in Turkish forestry. In general, Scots pine seedlings were tolerant to glyphosate compared to the other species. Glyphosate phytotoxicity varied significantly according to the time and rate of application. Seedlings were relatively tolerant to glyphosate in April whereas they were intolerant in May. The highest herbicide rate (1.2% v:v) was consistently phytotoxic to all species. Moreover, the effect of herbicide rate on seedling survival and growth varied significantly according to application date (i.e., application rate × date interaction). Seedlings appeared tolerant to glyphosate at low and intermediate rates (0.2, 0.4% v:v) between mid-spring and mid-summer, whereas they demonstrated significant sensitivity to the highest rate across all time periods. Glyphosate at the high rate (0.8% v:v) was particularly more phytotoxic when applied in May. Application of glyphosate at rates up to 0.8% could be recommended for weed control without significant pine damage in mid-spring when the needles presumably have a dense leaf epicuticular wax layer limiting herbicide penetration. Applications of 0.8 and 1.2% v:v are not recommended during May-June. [ABSTRACT FROM AUTHOR]

Key message: After 3 years of elevated CO2 treatments, spruce Pn regulation from aCO2 to eCO2 was strongly related to total dry mass change (%), whereas pines displayed the same trend, but the relationship was not statistically significant.Abstract: Assimilation to internal CO2 (ACi) response curve parameters were grown and quantified under ambient (aCO2) and elevated (eCO2) CO2 treatments for two commercially important tree genera, Pinus and Picea spp. The species include Pinus strobus (WP), P. resinosa (RP), P. banksiana (JP), P. rigida (PP), Picea glauca (WS), P. rubens (RS), P. mariana (BS), and P. abies (NS). Seedlings were 4 years old and dosed for 3 years at the time of measurements. Overall, pines had greater maximum rates of carboxylation (Vcmax) and maximum assimilation (Amax) values than spruces, and there was a significant downregulation in Vcmax and Amax for both genera in eCO2, but more so for the spruces. For the maximum rate of electron transport (Jmax) and the rate of triose phosphate utilization (TPU), there was no significant genus effect, but there was a significant downregulation in eCO2. For these four traits, all spruces downregulated, whereas each pine species responded quite differently. White pine downregulated the most, followed by RP; no change for JP, and PP traits increased under eCO2. At an intermediate CO2 level, net photosynthesis @570 ppm CO2 (Pn570) was 13.0% greater for pines and 9.0% lower for spruces under eCO2 compared with aCO2. Comparing responses under eCO2 to aCO2, Pn570 was equal for WS but lower for the other spruces; however, WP declined, RP showed no difference, JP had greater Pn570, and PP had substantially greater Pn570. For pines, there appears to be a consistent enhanced sink effect on Pn across all species. Corresponding Pn570 change from aCO2 to eCO2 across spruce species showed a strong positive and statistically significant correlation to biomass stimulation that supports the theory of sink regulation of Pn. [ABSTRACT FROM AUTHOR]

During the process of climate change in East Asia since the 1980s, increasing climate influence and meteorological hazardous events occurred, such as persistent drought, strong typhoon, and intercurrent meteorological extremes. The maximum temperature and persistence of rain-free days rose during the most recent 30 years in many cities in China. The combination of these extremes may evidently decrease the threshold of tree responses to the extreme stresses, even cause pine wilt in the area. By studying the geographic distribution of pine wilt disease, climate change characteristics, and the relationship between resin excretion and meteorological hazardous events, the relationship between pine wilt events and the summer droughts and strong typhoons in East Asia was investigated. The spatial and temporal consistency of the prevalence of pine wilt disease with climate change characteristics in both China and Japan suggests that pine wilt is related to local environmental variance. After extreme summer drought and strong typhoons, the ability of pines to excrete oleoresin was often reduced, and deaths were observed. The special adaptive characteristics of pines to meteorological hazard events during climate change, such as stopping or reducing resin excretion, may be the key of their wilt. [ABSTRACT FROM AUTHOR]

The North American fungal pathogen Heterobasidion irregulare is invading and threatening pine stands in Italy and is freely hybridizing with the native species Heterobasidion annosum. Susceptibility of native hosts has been excluded as a factor driving H. irregulare invasion. Here we tested whether H. irregulare and H. annosum differ in their ability to saprobically colonize pine wood, and whether saprobic growth is correlated to fruiting bodies production. When inoculated in pine logs, H. irregulare genotypes colonized a volume of wood significantly larger than H. annosum genotypes. Heterobasidion irregulare significantly exceeded H. annosum in all parameters used as metrics of fruiting body production, including number and size of fruiting bodies, and pores perimeter index ( PPI), an index summarizing the amount of surface available for spore production. Number of fruiting bodies and PPI were significantly correlated with volume of wood colonized by Heterobasidion genotypes. Results may explain why H. irregulare has been reported to sporulate more abundantly than H. annosum and provide explanations for its high transmission potential in Italy. This knowledge implies that approaches to control the spread of H. irregulare should be aimed at limiting saprobic establishment of the fungus rather than focusing on identifying more tolerant tree species. [ABSTRACT FROM AUTHOR]

Genetic variation in 12 Pinus pinaster (maritime pine) populations spanning most of the distribution range of the species in Portugal was evaluated using six polymorphic chloroplast microsatellite (cpSSR) loci. Thirty-two haplotypes were found. There were indications of very weak differentiation among populations (Weir’s θcoefficient, 0.023), and the RST value, derived from the stepwise mutation model (SMM), was not significantly different from zero. The pattern, in which similarities in allele size, in base pairs, do not contribute to the genetic structure, may be due to the recent mixing of genetic material from different stands through plantations. Overall, a high level of haplotypic variation within populations was detected. Using the SMM estimator (mean genetic distance of individuals within populations, D2sh–––) we divided the populations into two groups, with above and below average values. The first group contained 5 populations, mainly from the central part of the country, which possess, in general, high levels of haplotypic diversity. Among them, 2 populations were divergent from the others based on the pair-wise Nei’s distance. The results indicate that there is no discernible geographic genetic pattern for the Portuguese populations of P. pinaster investigated. The history of expansion of the species range in Portugal during the twentieth century (mainly due to human activity) and extensive gene flow among populations associated with the expansion could explain this finding. [ABSTRACT FROM AUTHOR]

We have investigated the physical distribution of the reverse transcriptase genes of Ty1-copia-like retrotransposable elements from 12 plant species belonging to different subdivisions by hybridization in situ on chromosome preparations. Ty1-copia-like elements showed different and non-random hybridization patterns. A dispersed distribution throughout most of the chromosomes with reduced hybridization at some regions or with some weak clustering at other regions was found in Allium cepa, Beta vulgaris, Brassica campestris, Brassica oleracea, Pennisetum glaucum, Pinus elliottii, Selaginella apoda, Vicia faba and Vicia narbonensis. Reduced hybridization occured mainly at centromeric regions, nucleolus-organizing regions and regions known to be mainly composed of tandemly repeated sequences. In the fern Pteris cretica the retroelements showed a dispersed genomic organization with clustering at some chromosomal regions and whole chromosomes showing little signal. In Arabidopsis thaliana and Cicer arietinum, Ty1-copia-like elements were found in clusters at the paracentromeric heterochromatin, a novel organization for a repetitive element in A. thaliana. New retroelement families were isolated from A. thaliana and from Beta vulgaris. Alignment of the deduced peptide sequences with Ty1-copia-like elements from other plants showed considerable divergence which was used to calculate their relationships, indicating the value of reverse transcriptase gene analysis in phylogenetic and biodiversity studies. [ABSTRACT FROM AUTHOR]

In the genus Pinus the internal transcribed spacers (ITS1 and ITS2) and the 5.8 s region of the nuclear ribosomal DNA are approximately 3000 bp in length. ITS1 is considerably longer than ITS2 and partial sequences of ITS1 indicate that this region is evolving rapidly and exhibits intraspecific variation. The ITS2 and 5.8 s regions are relatively conserved. We surveyed restriction fragment length variability of PCR-amplified fragments (PCR-RFLP) of the ITS region in four populations (86 individuals) of Pinus rzedowskii, a pine endemic to western Michoacán, Mexico. Five of the restriction endonucleases assayed revealed variation, with a total of 13 variants, most of which were length mutations of 300–900 bp. A moderate degree of population differentiation was detected. The average diversity (Shannon’s index) of ITS fragment size patterns was 1.19, with 34% of the variation due to differences among populations and 66% due to differences among individuals within populations. The same individuals were assayed for nine polymorphic isozymes, which gave diversity measures similar to those of each restriction endonuclease. [ABSTRACT FROM AUTHOR]

Haploid linkage analysis of eastern white pine, Pinus strobus L., was carried out using mainly RAPD markers and microsatellite, or simple-sequence-repeat, markers. Ninety one loci mapped to 12 linkage groups of three or more markers. The resulting framework genome map, the first for a soft pine species, contained 69 markers. The map covered 58% of the estimated genome length of 2071 cM(K), with a 95% confidence interval of 1828–2242 cM(K). A systematic comparison of linkage data from eastern white pine, longleaf pine ( P. palustris Mill.) and maritime pine ( P. pinaster Ait.), gave genome-length estimates for all three species very close to either 2000 cM(K) or 2600 cM(H), depending on whether the Kosambi(K) or Haldane(H) map functions, respectively, were employed. Differences among previous pine genome-length estimates were attributed to the divergent criteria used in the methods of estimation, and indicate the need for the adoption of uniform criteria when performing genome-length estimates. Current data suggest that members of the two pine subgenera, which diverged during the late Mesozoic era, have highly conserved rates of recombination. [ABSTRACT FROM AUTHOR]

Forest tree breeding is relatively a young science. Even so, there is good evidence of its potentiality for increasing forest productivity and quality of the forest produce. The basic scheme for forest tree improvement involves selection of superior parent trees, assembling them as clones in seed orchards in special designs to promote maximum cross pollination among the different clones and reduce inbreeding. Interprovenance and interspecific hybridisation are also resorted to in special situations. Forest tree improvement work through selection and breeding has been in progress in India for the last nearly two decades. Some of the achievements and strategies used are briefly reviewed. [ABSTRACT FROM AUTHOR]