Cathaya Research Articles

First Report of Root Rot of Cathaya argyrophylla caused by Fusarium oxysporum in China.

Cathaya argyrophylla [Chun & Kuang.] is an ancient relict plant and its embryonic development is similar to that of Pinus species. This has important scientific value for studying the phylogeny of Pinaceae (Wu et al. 2023). In July 2022, root rot was detected in the seedling cultivation base of C. argyrophylla in Daozhen County, Guizhou Province, China (28.89 °N, 107.6 °E). The incidence of the disease was 30% (n = 100); the susceptible plants wilted, leaves withered, and roots showed brown-to-black lesions and rot. Ten root tissues were randomly collected from the edges of the lesions of six symptomatic susceptible plants. The tissues were sterilized with 75% alcohol for 30 seconds, followed by 2-minute immersion in 3% sodium hypochlorite. After washing with sterile water, the tissues were incubated on potato dextrose agar (PDA; BoWei, Shanghai) at 28 ℃ for five days. Four single-spore cultures were obtained using a single-spore isolation method (Gong et al., 2010). Single-spore cultures grew rapidly on PDA. After five days of incubation, the colonies were white and pink, indicating a large amount of aerial mycelia. Microconidia were ovate or ellipsoid, measuring 5.0-10.0 × 1.5-3.0 μm (n = 50); Macroconidia were falcate, slightly curved or straight, measuring 19.5-28.5 × 2.0-6.0 μm (n = 50). Based on morphological features, the pathogen was considered to be Fusarium spp. (Leslie and Summerell 2006). Three representative strains, GF5, GF6, and GF7, were selected for molecular identification, and genomic DNA was extracted to confirm morphological diagnosis. The internal transcribed spacer (ITS) (White et al. 1990) was amplified using primers ITS1/ITS4, and the β-tubulin gene (Varga et al. 2011) was amplified using primers Bt2a/Bt2b. The ITS and β-tubulin sequences were aligned with GenBank, and amplification of the genes from the three isolates was consistent. The ITS (OP482273) and β-tubulin (OR825353) sequences of GF5 were stored in GenBank, and their homology with Fusarium oxysporum HC131(accession numbers MW600442 and MW670451) was 99 to 100%. Maximum likelihood analysis using MEGA 11.0 showed that isolate GF5 belongs to F. oxysporum. The reconstructed phylogenetic tree confirmed the phylogenetic position of the isolate GF5. The pathogenicity test was carried out using GF5 and GF6 isolates. The taproots of ten 3-year-old C. argyrophylla plants were washed, and then the roots were immersed in a 2 × 106/mL conidial suspension for one hour. Ten plants with sterile water were used as controls. After planting in pots (30 × 25 cm) with sterilized forest soil, the plants were cultured in a greenhouse (25 ℃ and 12-hour photoperiod). Thirty days after inoculation, all plants inoculated with the isolated pathogen showed wilting symptoms, and the roots showed typical root rot symptoms, whereas the control group showed no symptoms. The pathogens re-isolated from all inoculated plants were morphologically identical and had ITS sequences identical to F. oxysporum, validating Koch's hypothesis. The pathogenicity test was repeated twice and similar results were obtained. Although this fungus has been previously reported to cause root diseases in hosts, such as Musa nana Lour. and Pinus massoniana Lamb. (He et al. 2010; Luo et al. 2020), to our knowledge, this is the first report of F. oxysporum causing root rot in C. argyrophylla. These findings provide a basis for the development of management strategies for C. argyrophylla infection.

History cooling events caused migrations of endangered Cathaya argyrophylla into low latitude refuges

Cathaya argyrophylla, referred as “the giant panda of plants”, is an endangered relict conifer species endemic to subtropical mountainous in China. The remanent populations of C. argyrophylla only survive in four refuges, while how the species migrated into these refuges remains unknown. To investigate the genetic structure and history of C. argyrophylla, here we genotyped four natural populations of C. argyrophylla using restriction site-related DNA sequencing (RAD-Seq). The four populations exhibited a relatively high level of nucleotide diversity (π = 0.29–0.33) and low differentiation (Fst = 0.04–0.12), with relatively high gene flow frequency (Nm = 1.86–6.00). We identified two historical migration events from high latitude populations to low latitude ones. The divergence times were corresponded to the starting time of population decline, which coincided with Naynayxungla Glaciation (∼0.8–0.5 Mya), the last glacial period (LGP, ∼115–11.7 kya) and the Holocene (∼10 kya). These results indicate that historical cooling events drove the endemic status of C. argyrphylla and its migration into low latitude refuges. Our findings provide insights into the evolutionary history and genetic diversity of this endangered species.

The diversity and abundance of bacterial and fungal communities in the rhizosphere of Cathaya argyrophylla are affected by soil physicochemical properties.

Cathaya argyrophylla is an ancient Pinaceae species endemic to China that is listed on the IUCN Red List. Although C. argyrophylla is an ectomycorrhizal plant, the relationship between its rhizospheric soil microbial community and soil properties related to the natural habitat remains unknown. High-throughput sequencing of bacterial 16S rRNA genes and fungal ITS region sequences was used to survey the C. argyrophylla soil community at four natural spatially distributed points in Hunan Province, China, and functional profiles were predicted using PICRUSt2 and FUNGuild. The dominant bacterial phyla included Proteobacteria, Acidobacteria, Actinobacteria, and Chloroflexi, and the dominant genus was Acidothermus. The dominant fungal phyla were Basidiomycota and Ascomycota, while Russula was the dominant genus. Soil properties were the main factors leading to changes in rhizosphere soil bacterial and fungal communities, with nitrogen being the main driver of changes in soil microbial communities. The metabolic capacities of the microbial communities were predicted to identify differences in their functional profiles, including amino acid transport and metabolism, energy production and conversion, and the presence of fungi, including saprotrophs and symbiotrophs. These findings illuminate the soil microbial ecology of C. argyrophylla, and provide a scientific basis for screening rhizosphere microorganisms that are suitable for vegetation restoration and reconstruction for this important threatened species.

Tracing the geographic origin of endangered plant species using transcriptome-derived SNPs: An example of Cathaya argyrophylla.

Genetic markers have emerged as one of the most promising tools for species identification and geographic traceability in biodiversity conservation and international trade of biological products. However, traditional molecular markers rarely have sufficient resolution at lower taxonomic levels, especially for discriminating closely related forest tree species and their populations. In this study, we developed a panel of RNA-Seq based single nucleotide polymorphism (SNP) markers for tracing the geographic origin of an endangered conifer, Cathaya argyrophylla, which is a paleoendemic restricted to four mountain regions in subtropical China. A total of 69 individuals from five populations (DLS, SHS, HP, BMS, and DYS) covering the entire range were used for transcriptome sequencing. Based on these transcriptomic data, we evaluated genetic variation and population structure of C. argyrophylla, and found extremely low nucleotide diversity but strong population differentiation. We also screened 113 population-specific SNP loci, including 96 for BMS, eight for DYS, six for SHS, two for HP, and one for one of the three subpopulations from DLS. According to these geographically diagnostic SNPs, we designed four population-specific molecular barcodes for PCR amplification. To test the utility and efficiency of the four markers in geographic discrimination, double-blind experiment was performed using 157 individuals labelled without any locality information. We found that almost all tested individuals could be successfully assigned to their geographic localities. Our study not only sheds some new light on the genetic profile of C. argyrophylla, but also provides a practical and cost-efficient solution for geographic traceability using transcriptome-derived SNPs.

Assessing habitat suitability and selecting optimal habitats for relict tree Cathaya argyrophylla in Hunan, China: Integrating pollen size, environmental factors, and niche modeling for conservation

The endangered plant Cathaya argyrophylla Chun et Kuang is the only species in the genus and is endemic to China, and because of challenged regeneration and shrinking habitats, the protected areas (PAs) need to be expanded in Hunan Province. In this study, a maximum entropy model (MaxEnt) was used to predict the potentially suitable habitats and population centroid migrations for C. argyrophylla in Hunan under four climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) at four time points (2030, 2050, 2070, and 2090) based on thirteen environmental variables. For the first time, optimal habitats that could support breeding Cathaya populations with good fruiting quality in Hunan were identified considering relations between pollen grain size and environmental variables. Of the total area, 10.69 % (22.63 × 103 km2) was suitable for C. argyrophylla, which was distributed primarily in western and southern parts of Hunan. Monthly precipitation in August was the environmental variable that contributed the most (28.2 %) to C. argyrophylla distribution. Other influential variables were annual mean temperature, annual precipitation, mean temperature of the wettest quarter, monthly solar radiation in May, and precipitation of the driest month. The suitable distribution area for C. argyrophylla decreased overall under the climate change scenarios, with SSP2-4.5 the exception. Population centroid of C. argyrophylla shifted overall slightly toward southeast areas with more abundant precipitation in Hunan under climate change. The average shift distance was 3.89 km, and the longest migration distance (8.84 km) was in 2090 under SSP1-2.6. In Hunan, 642.12 km2 were authority identified as optimal habitat based on the current climate. It is proposed that areas with altitudes between 758 m and 1,500 m be treated as crucial PAs networks for C. argyrophylla, mainly including Nanyue, Yanling, Guidong, Xinning, and Zixing counties and districts. The goal of the study was to assist in the conservation and management of C. argyrophylla, but it also provides an example of how to evaluate optimal habitats for those endangered species that need to produce populations with specific superior characteristics.

Differences in the Chloroplast Genome and Its Regulatory Network among Cathaya argyrophylla Populations from Different Locations in China.

Cathaya argyrophylla Chun et Kuang is a severely endangered, tertiary relict plant unique to China whose high physiological sensitivity to the environment, including photosensitivity, is likely closely related to its endangered status; however, the exact mechanism responsible has remained unknown due to the rarity of the plant and the difficulties involved in performing physiological studies on the molecular level. In this study, the chloroplast genomes of six C. argyrophylla populations sampled from different locations in China were characterized and compared. In addition, a gene regulatory network of the polymorphic chloroplast genes responsible for regulating genes found elsewhere in the plant genome was constructed. The result of the genome characterization and comparison showed that the genome characteristics, the gene composition, and the gene sequence of the chloroplast genes varied by location, and the gene regulatory network showed that the differences in growth location may have led to variations in the protein-coding chloroplast gene via various metabolic processes. These findings provide new insights into the relationship between chloroplasts and the sensitive metabolism of C. argyrophylla and provide additional reference materials for the conservation of this endangered plant.

Intraspecific Pollen Morphology Variation and Its Responses to Environmental Factors of Wild Cathaya argyrophylla Chun Et Kuang Endemic to China

Studying the pollen morphology of this remnant and endemic wild species of Cathaya argyrophylla can be of use for paleobiologists. During this study, 23 genotypes sampled from four natural populations in two regions of Hunan Province, China. A total of 460 pollen grains were analyzed for seven quantitative and seven qualitative traits (including five new traits). Three quantitative traits (B, P, and A) (Width of the saccus (B); Length of the polar axis (P); Length of the saccus (A)) and four qualitative traits (O-CO, B-SD, O-CSR, and B-SU) (Pollen corpus outlined in the polar distal view (O-CO); Whether the outline of two sacci was distinct or not in the polar proximal view (B-SD); Roughness degree between corpus from the polar proximal view and the sacci from the polar distal view (O-CSR); Whether the overall size of two sacci was uniform or not (B-SU)) were the diagnostic pollen features that could possible to differentiate one population and classified 23 samples into two, three, or four clusters. Furthermore, 24 environmental factors were evaluated and precipitation factors effected more on pollen morphology than geographic and temperature factors, which including annual precipitation (bio12), precipitation of wettest month and driest month (bio13, bio14), precipitation seasonality (bio15) and monthly averaged precipitation in May (05-precip). The main precipitation and temperature factors exhibited positive and negative correlation with pollen size (B and E (Equatorial diameter (E))), respectively. This article provides deeper insight into intraspecific variability of pollen grains of C. argyrophylla, which have been investigated for the first time. In addition, the insights gained from this study could assist with the seed breeding and population reproduction of the endangered C. argyrophylla tree.

Identifying conservation priority areas for gymnosperm species under climate changes in China

China has a rich flora of gymnosperms. Gymnosperm species dominate and co-dominate more than half of China's forest area, but many of them are threatened and vulnerable to climate changes. This study mapped the geographical distributions of 209 gymnosperm species in China, modeled the niches of 124 gymnosperm species with adequate records of field occurrences using MaxEnt, and predicted their range changes under two dispersal scenarios (no dispersal and unlimited dispersal) and three emission scenarios (Representative concentration pathway [RCP] 2.6, RCP 6.0, RCP 8.5). To inform gymnosperm conservation facing climate change, we proposed a multi-criteria framework to identify conservation priority areas by integrating information on species diversity patterns and potential climate refugia, and detected gymnosperm conservation gaps with reference to the existing conservation networks. Our results indicated that the centers of species richness, threatened species, and endemism of gymnosperms in China were highly consistent in space and were concentrated in the subtropical mountains. By the 2070s, 64 (RCP 2.6)–88 (RCP 8.5) species would lose more than 10% of their currently suitable climatic niche, and 19 (RCP 2.6)–45 (RCP 8.5) species would lose more than 30%. Cathaya argyrophylla (endangered, EN), Pinus bungeana (EN), Pinus koraiensis (vulnerable, VU) and Torreya fargesii (VU) would be most vulnerable to the projected climate changes. Seven high conservation priority regions were identified, and a substantial proportion of the regions were found lack of adequate protection. The primary recommended measures included increasing the size of protected areas to cover more high priority regions and establishing populations in new sites as required ex-situ conservation efforts.

气候变化对孑遗植物银杉的潜在分布及生境破碎度的影响

气候变化对孑遗植物银杉的潜在分布及生境破碎度的影响

Planning priority conservation areas under climate change for six plant species with extremely small populations in China

The concept of Plant Species with Extremely Small Populations (PSESP) has been employed to guide conservation of threatened plant species in China. Climate change has a high potential to threaten PSESP. As a result, it is necessary to integrate climate change effects on PSESP into conservation planning in China. Here, ecological niche modelling is used to project current and future habitat distributions of six PSESP in China under climate change scenarios and conservation planning software is applied to identify priority conservation areas (PCAs) for these PSESP based on habitat distributions. These results were used to provide proposals for in-situ and ex-situ conservation measures directed at PSESP. It was found that annual precipitation was important for habitat distributions for all six PSESP (with the percentage contribution to habitat distributions ranging from 18.1 % to 74.9 %) and non-climatic variables including soil and altitude have a large effect on habitat suitability of PSESP. Large quantities of PCAs occurred within some provincial regions for these six PSESP (e.g. Sichuan and Jilin for the PSESP Cathaya argyrophylla, Taxus cuspidata, Annamocarya sinensis and Madhuca pasquieri), indicating that these are likely to be appropriate areas for in-situ and ex-situ conservation measures directed at these PSESP. Those nature reserves with large quantities of PCAs were identified as promising sites for in-situ conservation measures of PSESP; such reserves include Yangzie and Dongdongtinghu for C. argyrophylla, Songhuajiangsanhu and Changbaishan for T. cuspidata and Shiwandashanshuiyuanlian for Tsoongiodendron odorum. These results suggest that existing seed banks and botanical gardens occurring within identified PCAs should allocate more resources and space to ex-situ conservation of PSESP. In addition, there should be additional botanical gardens established for ex-situ conservation of PSESP in PCAs outside existing nature reserves. To address the risk of negative effects of climate change on PSESP, it is necessary to integrate in-situ and ex-situ conservation as well as climate change monitoring in PSESP conservation planning.

Effective conservation measures are needed for wild Cathaya argyrophylla populations in China: Insights from the population structure and regeneration characteristics

Owing to the existence of global Pleistocene refugia, the relict and ancient component of the modern endemic flora is considerable in South-Central China. Study of these relict species helps to understand past and recent ecological processes affecting species persistence, and also provides knowledge to guide human-assisted management and conservation practice. In this study, we investigated the current status of the remnant populations of Cathaya argyrophylla, one of the emblematic “living fossils”, growing in the Dalou Mountains of South-Central China. We quantified the population structure of C. argyrophylla and investigated demographic changes of seedlings over a ten year period to learn the plant’s regeneration patterns following the establishment of two national and provincial nature reserves in late 1970s. Notable “gaps” in age structure over 40years were found, suggesting significant recruitment failures in these scattered population since the establishment of the nature reserves. Further, the number of dead individuals peaked at ages between 40 and 80years and the seedlings showed high mortality in the past 10years, probably due to intensified competition from the nearby broad-leaved trees and the reduction of suitable micro-habitats. These facts indicated that attention needs to be paid and follow-up measures should be taken to more effectively conserve C. argyrophylla in the future.

Terpene and lignan glycosides from the twigs and leaves of an endangered conifer, Cathaya argyrophylla

Labdane diterpene glycosides cathargyroside A and cathargyroside B, monoterpene glycosides vervenone-10-O-β-D-glucopyranoside and vervenone-10-O-β-D-apiofuranosyl-(1″→6')-β-D-glucopyranoside, as well as lignan glycosides cedrusinin-4-O-α-L-rhamnopyranoside and (+)-cyclo-olivil-9'-O-β-D-xylopyranoside, along with 39 known compounds, were obtained from the methanol extract of the twigs and leaves of Cathaya argyrophylla. These compounds were identified mainly by analyzing their NMR and MS data. Almost all of these compounds were hitherto unknown in this genus. The isolated compounds were screened against Candida albicans and Staphylococcus aureus for antimicrobial assay, and against K562, HT-29, BEL-7402, SGC-7901, B16, BGC-823, U251 and A549 cancer cell lines for cytotoxic activities. One compound showed antimicrobial activity against C. albicans, and four of them displayed cytotoxicity. Similarity analysis on the chemical constituents of the genera Cathaya, Picea and Pinus supported their close phylogenetic relationships.

A new species of Lophodermium associated with the needle cast of Cathay silver fir

Cathay silver fir, Cathaya argyrophylla, is a national first-class protected species in China and honored as a “living fossil” of the plant kingdom. Recently, a needle cast of Cathay silver fir of the Guangxi Zhuang Autonomous Region, China was investigated. This pathogen not only reduces the host ornamental value, but seriously affects the growth of this endangered plant. In this paper, the needle cast, formerly misidentified as Lophodermium pinastri, is identified as Lophodermium cathayae. L. cathayae differs morphologically from L. pinastri in many aspects, but particularly in anamorph morphology. An analysis of the internal transcribed spacer of rDNA shows that L. cathayae is closely related to L. pinastri and that further study is required in order to update the circumscription of L. pinastri. The fungal diversity conservation for new species L. cathayae is discussed.

Isolation and characterization of 50 nuclear microsatellite markers for Cathaya argyrophylla, a Chinese endemic conifer

Microsatellite primers were developed for the endangered Cathaya argyrophylla (Pinaceae) to investigate its genetic diversity and population genetic structure, as well as its evolutionary history. • Fifty dinucleotide microsatellite loci were identified in two populations. The number of alleles per locus ranged from 1 to 6, with a mean of 2.84. The observed and expected heterozygosities ranged from 0 to 0.889 and from 0 to 0.779, respectively. • These markers will facilitate further studies on the population genetics and evolutionary history of Cathaya argyrophylla.

Formation of Mycorrhiza-like Structures in Cultured Root/Callus of Cathaya argyrophylla Chun et Kuang Infected with the Ectomycorrhizal Fungus Cenococcum geophilum Fr.

An in vitro system was used for ectomycorrhizal synthesis of Cenococcum geophilum Fr. with Cathaya argyrophylla Chun et Kuang, an endangered species. Calli initiated from stem segments and adventitious roots differentiated from young seedlings were removed and cocultured with Cenococcum geophilum on a modified Murashige-Skoog medium. Fungal hyphae were visible within intercellular spaces of the callus 4 weeks after inoculation, but definite and well-developed Hartig net structures did not form in the calli 8 weeks after inoculation. The typical ectomycorrhizal structures (i.e. hyphal mantle and intracortical Hartig net) were observed in root segments 8 weeks after inoculation. This is the first report of aseptic ectomycorrhizal-like formation/infection between root organ/callus of Cathaya argyrophylla and the ectomycorrhizal fungus Cenococcum geophilum. This culture system is useful for further investigation of mycorrhizal synthesis in Cathaya trees. (Managing editor: Ya-Qin Han)

Phylogeography of the endangered Cathaya argyrophylla (Pinaceae) inferred from sequence variation of mitochondrial and nuclear DNA

Cathaya argyrophylla is an endangered conifer restricted to subtropical mountains of China. To study phylogeographical pattern and demographic history of C. argyrophylla, species-wide genetic variation was investigated using sequences of maternally inherited mtDNA and biparentally inherited nuclear DNA. Of 15 populations sampled from all four distinct regions, only three mitotypes were detected at two loci, without single region having a mixed composition (G(ST) = 1). Average nucleotide diversity (theta(ws) = 0.0024; pi(s) = 0.0029) across eight nuclear loci is significantly lower than those found for other conifers (theta(ws) = 0.003 approximately 0.015; pi(s) = 0.002 approximately 0.012) based on estimates of multiple loci. Because of its highest diversity among the eight nuclear loci and evolving neutrally, one locus (2009) was further used for phylogeographical studies and eight haplotypes resulting from 12 polymorphic sites were obtained from 98 individuals. All the four distinct regions had at least four haplotypes, with the Dalou region (DL) having the highest diversity and the Bamian region (BM) the lowest, paralleling the result of the eight nuclear loci. An AMOVA revealed significant proportion of diversity attributable to differences among regions (13.4%) and among populations within regions (8.9%). F(ST) analysis also indicated significantly high differentiation among populations (F(ST) = 0.22) and between regions (F(ST) = 0.12-0.38). Non-overlapping distribution of mitotypes and high genetic differentiation among the distinct geographical groups suggest the existence of at least four separate glacial refugia. Based on network and mismatch distribution analyses, we do not find evidence of long distance dispersal and population expansion in C. argyrophylla. Ex situ conservation and artificial crossing are recommended for the management of this endangered species.

Genetic Diversity of RAPD Mark for Natural Davidia involucrata Populations

The genetic diversity and genetic variation within and among populations of five natural Davidia involucrata populations were studied from 13 primers based on random amplified polymorphic DNA (RAPD) analysis. The results show that natural D. involucrata population has a rich genetic diversity, and the differences among populations are significant. Twenty-six percent of genetic variation exists among D. involucrata populations, which is similar to that of the endangered tree species Liriodendron chinense and Cathaya argyrophylla in China, but different from more widely distributed tree species. The analysis of the impacts of sampling method on genetic diversity parameters shows that the number of sampled individuals has little effect on the effective number of alleles and genetic diversity, but has a marked effect on the genetic differentiation among populations and gene flows. This study divides the provenances of D. involucrata into two parts, namely, a southeast and a northwest provenance.

In situ and in vitro colonization of Cathaya argyrophylla (Pinaceae) by ectomycorrhizal fungi

Cathaya argyrophylla, a critically endangered conifer, is found to grow at four isolated areas located in subtropical mountains of China. To examine the involvement and usefulness of mycorrhizas for sustaining the population of this tree, we compared the root system, morphology, and structure of mycorrhizal roots of C. argyrophylla, which were collected from a natural stand and an artificial stand, each grown at a different location. More mycorrhizal roots were found for trees from an artificial stand. The presence of extramatrical mycelium, mantle, and Hartig net revealed that C. argyrophylla formed an ectomycorrhizal association in both sampling sites. Starch granules were found in mycorrhizal roots collected only from a natural stand. The aseptic synthesis of C. argyrophylla and Cenococcum geophilum was established for the first time in vitro. Typical ectomycorrhizas formed on seedlings on RM medium containing 0.1 g/l glucose, 5 weeks after inoculation. By light microscopy, the synthesized mycorrhizas showed a thin mantle from which emanated extramatrical hyphae and highly branched Hartig net. A simple, rapid, and convenient mycorrhiza synthesis system was developed, which facilitates further studies on ectomycorrhizal development of C. argyrophylla.

The seasonal photosynthetic responses of seedlings of the endangered plant Cathaya argyrophylla to different growth light environments

The seasonal photosynthetic responses of seedlings of the endangered plant Cathaya argyrophylla to different growth light environments

THE DENDROCHRONOLOGICAL POTENTIAL OF TEN SPECIES IN THE THREE GORGES RESERVOIR REGION OF CHINA

About 250 trees, representing 10 species, were collected from the Chinese Three Gorges Reservoir region as part of a study to use tree rings as indicators of environmental change in this area. Five species do not show distinct ring boundaries or cannot be cross-dated with each other. The dendrochronological potential of the remaining five species, two conifers and three hardwoods, are assessed in this paper. These five species, Cathaya argyrophylla, Cinnamomum camphora, Gordonia acuminata, Pinus massoniana, and Schefflera delavayi, have distinct annual growth rings and little occurrence of double or missing rings. Treering width and maximum latewood density chronologies from the five species range in length from 38 to 138 years. These relatively short chronologies are just long enough to conduct a preliminary dendroclimatic evaluation. Preliminary climate modeling demonstrates some significant relationships between tree-ring data and temperature, precipitation, and river flow.