Thirty-year effects of liming on soil and foliage chemistry and growth of northern hardwoods in Pennsylvania, USA

The longevity of a single 22.4 Mg ha^-1 application of dolomitic limestone at four northern hardwood stands was evaluated over thirty years (1986-2016) to determine whether changes in soils, foliage, and tree growth were sustained on the unglaciated Allegheny Plateau in northern Pennsylvania, USA. In limed plots, soils, sampled to 45-55 cm depth, and sugar maple (<i>Acer saccharum</i> Marsh.) and black cherry (<i>Prunus serotina</i> Ehrh.) foliage had significantly ( P ≤ 0.05) greater concentrations of calcium (Ca) and magnesium (Mg) through 2016 compared with samples from unlimed plots. Calcium and Mg capitals (g m^-2) in the Oi through A horizon combined were greater on limed plots than unlimed plots, largely due to increases in the thickness and nutrient concentration in the A horizon. Over 30-years, sugar maple basal area increment (cm² yr^-1 BAINC) ) was greater in limed plots, American beech (<i>Fagus grandifolia</i> Ehrh.) BAINC was unaffected, and black cherry BAINC was reduced in limed plots compared with unlimed plots. The sustained effect of this one-time lime treatment shows the strong role of efficient nutrient cycling in forests and suggests that the benefits over a substantial portion of a stand rotation may increase the feasibility of operational liming.

Morphoanatomical and phylogenetic characterization of the ectomycorrhiza between Laccaria squarrosa with Pinus pseudostrobus and its relevance for reforestation programs

Background: Pinus (Coniferophyta) and Laccaria (Basidiomycota) establish ectomycorrhizal symbioses in natural forests. However, their detailed morphoanatomical and phylogenetic characterization have received little attention. Accurate identification of native host symbionts is of paramount relevance to the production of mycorrhized seedlings for successful reforestation programs. Questions/Objective: We aimed to determine if L. squarrosa is able to establish ectomycorrhizal symbiosis with gymnosperms, thereby widening its host range and highlighting its relevance as a potential inoculant for pine seedlings. Currently, L. squarrosa is only known from its type collection associated with the angiosperm Fagus grandifolia var. mexicana. Studied species: The fungus L. squarrosa and Pinus pseudostrobus, a tree endemic to Mexico. Study site and dates: A Pinus-Quercus forest in Piedra Canteada, Nanacamilpa, Tlaxcala; 2018-2020. Methods: L. squarrosa basidiomata were identified and ectomycorrhizal roots were collected and morphoanatomically characterized. For molecular identification, DNA was extracted, PCR was performed targeting the nuclear ribosomal internal transcribed spacer region (nucrDNA ITS) for the mycobiont identification and the chloroplastic single-locus trnL region for the phytobiont. Results: In the phylogenetic analyses, our sequences from basidiomata and ectomycorrhizae clustered together with L.squarrosa with high values of supporting identity. Meanwhile, P. pseudostrobus was molecularly identified as the phytobiont. Conclusions: This is one of the few worldwide characterizations of Laccaria ectomycorrhiza under field conditions and contributes to the understanding of the ecology, distribution, and economic relevance of the symbiotic association. Our data suggest that L. squarrosa has potential for use as a native inoculant for P. pseudostrobus tree production. Translate stop Translate stop

First Report of Beech Leaf Disease, Caused by Litylenchus crenatae mccannii, on American Beech (Fagus grandifolia) in Virginia

Beech leaf disease (BLD) was first reported in 2012 in Lake County, Ohio on American beech trees (Fagus grandifolia Ehrh.). Since then, it spread across the Northeastern United States and has been reported from Ohio, Pennsylvania, New York, New Jersey, Connecticut, Rhode Island, Maine, West Virginia, and Ontario, Canada (Carta et al. 2020; Mara and LaMondia 2020, Reid et al. 2020). The symptoms of BLD are characterized by dark interveinal banding of leaves appearing soon after spring flush that become chlorotic and necrotic through autumn, resulting in canopy thinning in advanced stages, followed in some young trees by death. Litylenchus crenatae mccannii has similar morphological characteristics with Litylenchus crenatae (Kanzaki et al. 2019) reported on Fagus crenata from Japan. However that beech species has not shown BLD symptoms or yielded any L. crenatae mccannii in North America. There are several morphological differences between the two. The North American subspecies have shorter post-uterine sac, narrower body width in mature females, shorter tail in immature females, longer tail in mature females, and longer stylet in males when compared to the Japanese subspecies (Carta et al. 2020). BLD symptoms were found on American beech trees in Prince William Forest Park, Prince William County, Virginia in June, 2021. The affected leaves contained females, males, and juveniles with morphometrics consistent with L. crenatae mccannii (Carta et al. 2020). The crude genomic DNA from a live single Litylenchus was prepared with freeze-thaw lysis (Carta and Li, 2019). The ITS PCR were performed by using the procedures and primer set, ITS-CL-F2 and 28S-CL-R described in the previous study (Carta and Li, 2020). The visualization, the cleanup and the direct DNA sequencing of the PCR products were performed by using the procedures described in the previous studies (Carta and Li, 2018 and 2019). Sequences were submitted to GenBank as accessions MZ611855 and MZ611856. This represents the first report of BLD in Virginia. It is also approximately 300 miles south of the 2020 detection of BLD from New Cumberland, WV, and represents the southernmost detection of the disease and nematode in North America. The author(s) declare no conflict of interest. References Carta, L.K., Li, S. 2018. Improved 18S small subunit rDNA primers for problematic nematode amplification. Journal of Nematology. 50, 533-542. Carta, L.K., Li, S. 2019. PCR amplification of a long rDNA segment with one primer pair in agriculturally important nematodes. Journal of Nematology. 51, e2019-26. Carta, L.K., Li, S. 2020. Improvement of long segment ribosomal PCR amplification for the molecular taxonomic identification of Litylenchus crenatae mccannii in beech trees with beech leaf disease. Journal of Nematology. 52, e2020-016. Kanzaki, N., Ichihara, Y., Aikawa, T., Ekino, T., Masuya, H. 2019. Litylenchus crenatae n. sp. (Tylenchomorpha: Anguinidae), a leaf gall nematode parasitising Fagus crenata Blume Nematology 21 (1), 5-22. http://www.brill.com/nematology doi: 10.1163/15685411-00003190 Marra, R.E., LaMondia, J. 2020. First report of beech leaf disease, caused by the foliar nematode, Litylenchus crenatae mccannii, on American beech (Fagus grandifolia) in Connecticut. Plant Disease (early view). https://doi.org/10.1094/PDIS-02-20-0442-PDN Reed, S. E., Greifenhagen, S., Yu, Q., Hoke A., Burke D. J., Carta L. K., Handoo Z.A., Kantor, M.R., Koch, J. 2020. Foliar nematode, Litylenchus crenatae ssp. mccannii, population dynamics in leaves and buds of beech leaf disease-affected trees in Canada and the US. Forest Pathology 50 (3), e12599.

Masting effect on alpha and beta avian diversity in fragmented forests of relict-endangered Mexican Beech (Fagus grandifolia subsp. mexicana)

Background Tropical montane cloud forests are one of the most important hotspots on Earth and show presence of relict-endemic and endangered species, representing about 14% of the total tropical forest worldwide. Synchronous seed production or masting in tropical montane cloud tree species is a widespread reproductive strategy of deciduous and evergreen broad-leaved tree associations to decrease costs of reproduction and ensure offspring. Masting event maintains a high avian diversity, which can be modified by phenological process (seed production and non-seed production). Methods The main aim of this study was to assess alpha and beta avian diversity and whether the composition of the trophic guild modifies among phenological processes and between two fragmented relict-endangered Mexican Beech (Fagus grandifolia subsp. mexicana) forests (Medio Monte and El Gosco) in the Mexican state of Hidalgo. In addition, we evaluated beechnut production. Results We recorded 36 bird species, 11 of them included in some conservation risk status, and 5 endemic species. Alpha diversity values were dissimilar in avian richness (q = 0) among phenological processes and between fragmented beech forests. Avian communities among three phenological processes and between fragmented forests were structurally similar, dominated during immature seeds the Brown-backed Solitaire (granivores–insectivores–frugivores); during mature seeds the White-crowned Parrot (Pionus senilis, granivores–frugivores); and the Dwarf Jay (Cyanolyca nana, insectivores) was abundant during low seed quality. The complementarity index was high among phenological processes and low between forests. We found a high bird turnover value between immature seeds—mature seeds and during mature seeds—low seed quality. Furthermore, a similar pattern was recorded between the two study forests. Seed production showed a high number of undamaged beechnuts in Medio Monte, while in El Gosco beechnuts were attacked by insects. Conclusions Our results reflect that masting phenological process and contrasting study forests’ structure influence the shifts in alpha and beta diversity of seed and non-seed bird consumers. Our study reaffirms the importance of continuing studies throughout masting in all the Mexican Beech forests to address regional efforts in preserving the relict-ecological interactions.

Relationships between pest density and associated leaf necrosis for an invasive leaf-mining weevil, Orchestes fagi L., on American beech (Fagus grandifolia Ehrh.)

Pest density-plant damage relationships are essential guides for decision-making in Integrated Pest Management. In this article, we established pest density-leaf damage relationships for the beech leaf-mining weevil,<i></i> Orchestes fagi <i></i>(L.) (formerly <i></i>Rhynchaenus fagi<i></i>, Coleoptera: Curculionidae) in its invasive range of Nova Scotia, Canada. Outbreaks of<i> O. fagi</i> cause tree-wide leaf necrosis in American beech (<i>Fagus grandifolia</i> Ehrh.), which can eventually result in tree mortality. In 2014 and 2016, we collected weekly samples in stands with American beech and assessed leaves for densities during different life stages (eggs, larvae, and pupae), population proxy measures (adult feeding damage, egg slits, and larval galleries), and percent necrosis. In general, feeding damage and leaf necrosis plateaued soon after end of budburst, but before larval mine expanded. This strongly suggested that leaf necrosis may be linked to damage caused by adults or mine initiation rather than that caused by larval mine expansion and gallery development. Density of <i>O. fagi</i> per leaf for life stages and population proxies all significantly explained ~ 42–81% of the variation in end-of season percent leaf necrosis. Results from this study provide a variety of relationships that could be used in both short- and long-term monitoring efforts for <i>O. fagi</i>.

Conditional inference trees in the assessment of tree mortality rates in the transitional mixed forests of Atlantic Canada

Long-term predictions of forest dynamics, including forecasts of tree growth and mortality, are central to sustainable forest-management planning. Although often difficult to evaluate, tree mortality rates under different abiotic and biotic conditions are vital in defining the long-term dynamics of forest ecosystems. In this study, we have modeled tree mortality rates using conditional inference trees (CTREE) and multi-year permanent sample plot data sourced from an inventory with coverage of New Brunswick (NB), Canada. The final CTREE mortality model was based on four tree- and three stand-level terms together with two climatic terms. The correlation coefficient (R2) between observed and predicted mortality rates was 0.67. High cumulative annual growing degree-days (GDD) was found to lead to increased mortality in 18 tree species, including Betula papyrifera, Picea mariana, Acer saccharum, and Larix laricina. In another ten species, including Abies balsamea, Tsuga canadensis, Fraxinus americana, and Fagus grandifolia, mortality rates tended to be higher in areas with high incident solar radiation. High amounts of precipitation in NB’s humid maritime climate were also found to contribute to heightened tree mortality. The relationship between high GDD, solar radiation, and high mortality rates was particularly strong when precipitation was also low. This would suggest that although excessive soil water can contribute to heightened tree mortality by reducing the supply of air to the roots, occasional drought in NB can also contribute to increased mortality events. These results would have significant implications when considered alongside regional climate projections which generally entail both components of warming and increased precipitation.

Modeling tolerant hardwood sapling density and occurrence probability in the Acadian forests of New Brunswick, Canada: Results 14 years after harvesting

Natural forest regeneration after natural or anthropogenic disturbance is difficult to predict given its high variability. The process is poorly documented for commercial northern hardwood species in the Acadian forest of eastern Canada. Our objective was to identify the silvicultural, environmental, and ecological factors that best explain the variability in sapling density and occurrence of two commercial tolerant hardwood species in New Brunswick: American beech (Fagus grandifolia Ehrh.) and sugar maple (Acer saccharum Marsh.). Forty-three permanent sample plots were established in 2002 and measured before harvesting in 2004. Sapling density and occurrence were measured 14 years after harvesting. The results showed that the interactions between the species and the residual merchantable basal area and between the species and the percent of hardwoods in the original stand best explained the sapling density and occurrence variation of tolerant hardwoods. The sapling density of sugar maple increased with increasing merchantable residual basal area. However, the effect of this variable was not significant for the density of American beech saplings. The density and occurrence of tolerant hardwood saplings both increased along with the percent of hardwoods in the original stand. These results provide an improved understanding about tolerant hardwood regeneration dynamics in New Brunswick forests.

Urbanization pressures alter tree rhizosphere microbiomes

The soil microbial community (SMC) provides critical ecosystem services including organic matter decomposition, soil structural formation, and nutrient cycling. Studies suggest plants, specifically trees, act as soil keystone species controlling SMC structure via multiple mechanisms (e.g., litter chemistry, root exudates, and canopy alteration of precipitation). Tree influence on SMC is shaped by local/regional climate effects on forested environments and the connection of forests to surrounding landscapes (e.g., urbanization). Urban soils offer an ideal analog to assess the influence of environmental conditions versus plant species-specific controls on SMC. We used next generation high throughput sequencing to characterize the SMC of specific tree species (Fagus grandifolia [beech] vs Liriodendron tulipifera [yellow poplar]) across an urban–rural gradient. Results indicate SMC dissimilarity within rural forests suggests the SMC is unique to individual tree species. However, greater urbanization pressure increased SMC similarity between tree species. Relative abundance, species richness, and evenness suggest that increases in similarity within urban forests is not the result of biodiversity loss, but rather due to greater overlap of shared taxa. Evaluation of soil chemistry across the rural–urban gradient indicate pH, Ca+, and organic matter are largely responsible for driving relative abundance of specific SMC members.