Climate impact on growth dynamic and intra-annual density fluctuations in Aleppo pine (Pinus halepensis) trees of different crown classes

Mediterranean environments are of special interest for the study of the relationships between climate, growth and anatomic features. Dendrochronological techniques were applied at eight sampling sites that were selected throughout the natural distribution area of Pinus halepensis in the Iberian Peninsula. The objectives of this paper were: (i) to identify relationships between radial growth and climate for different crown classes of Aleppo pine (P. halepensis Mill.); (ii) to quantify the presence of intra-annual density fluctuations (IADFs) according to crown class and cambial age; (iii) to establish the relationships between IADFs and climate. In the more mesic sites, dominant trees showed higher climatic sensitivity than suppressed trees, while in the more xeric sites suppressed trees showed higher sensitivity than dominant trees. Tree-ring growth of both crown classes correlated positively with precipitation during and prior to the growing season. IADFs were more frequent in young than in old stands without differences between crown classes. Precipitation in April and December was positively correlated to the occurrence of IADFs, while precipitation in July correlated negatively. A higher frequency in IADFs occurred in the last 50 years, which coincides with the increase in drought events in the Iberian Peninsula.     

Adjustment Capacity of Maritime Pine Cambial Activity in Drought-Prone Environments

Intra-annual density fluctuations (IADFs) are anatomical features formed in response to changes in the environmental conditions within the growing season. These anatomical features are commonly observed in Mediterranean pines, being more frequent in younger and wider tree rings. However, the process behind IADF formation is still unknown. Weekly monitoring of cambial activity and wood formation would fill this void. Although studies describing cambial activity and wood formation have become frequent, this knowledge is still fragmentary in the Mediterranean region. Here we present data from the monitoring of cambial activity and wood formation in two diameter classes of maritime pine (Pinus pinaster Ait.), over two years, in order to test: (i) whether the differences in stem diameter in an even-aged stand were due to timings and/or rates of xylogenesis; (ii) if IADFs were more common in large trees; and (iii) if their formation is triggered by cambial resumption after the summer drought. Larger trees showed higher rates of cell production and longer growing seasons, due to an earlier start and later end of xylogenesis. When a drier winter occurs, larger trees were more affected, probably limiting xylogenesis in the summer months. In both diameter classes a latewood IADF was formed in 2012 in response to late-September precipitation, confirming that the timing of the precipitation event after the summer drought is crucial in determining the resumption of cambial activity and whether or not an IADF is formed. It was the first time that the formation of a latewood IADF was monitored at a weekly time scale in maritime pine. The capacity of maritime pine to adjust cambial activity to the current environmental conditions represents a valuable strategy under the future climate change conditions.     

Climate control on ring width and intra-annual density fluctuations in <Emphasis Type="Italic">Pinus kesiya</Emphasis> growing in a sub-tropical forest of Manipur,Northeast India

Key message

Growth ring study of Pinus kesiya (khasi pine) growing in sub-tropical forest in Manipur, northeast India was performed to understand climate signatures in ring widths and intra-annual density fluctuations.

Abstract

The growth rings in khasi pine (Pinus kesiya Royle ex Gordon) growing in sub-tropical Reserve Forest in Imphal, Manipur, northeast India were analysed to understand environmental signals present in ring-width series and intra-annual density fluctuations (IADFs). For this the growth ring sequences in increment core samples collected from 28 trees were precisely dated and a ring-width chronology spanning AD 1958–2014 developed. The correlation analyses between ring-width chronology and weather data of Imphal revealed that a cool April–May–June favour tree growth. The wood anatomical features of growth rings revealed the occurrence of IADFs in early- and latewoods. The IADFs in earlywood were found to be associated with reduced precipitation in months from April to July. However, the wetter conditions in late growing season, especially August/September triggered the formation of IADFs in latewood. Our findings endorse that the IADF chronologies of khasi pine could emerge as an important proxy of summer monsoon rainfall in long-term perspective in data scarce region of northeast India.

     

Structural attributes,tree-ring growth and climate sensitivity of Pinus nigra Arn. at high altitude: common patterns of a possible treeline shift in the central Apennines (Italy)

European black pine (Pinus nigra ssp. nigra Arnold) encroachment at increasing elevation has been analyzed at four treeline ecotones of the central Apennines (Italy). The study sites are located along a North-South gradient of 170 km across Marche and Abruzzo regions in Central Italy. The aims of this study were: (i) to detect possible common patterns of structural attributes of black pine regeneration at the treeline ecotone; (ii) to date the seedlings germination and (iii) to assess the climate influence on the pine upward encroachment process also using intra-annual density fluctuations (IADFs) in tree-rings. We sampled 658 encroached black pine trees above the current treeline to the mountain top. All individuals were mapped and their basal stem diameter, total height, annual height increments and other structural attributes measured. One increment core was extracted from stem base of most samples for cambial age determination and detection of intra-annual density fluctuations (IADF). At two sites we also extracted cores at DBH from forest trees to assess climate–growth relationships of black pine. We used multivariate analysis (PCA) to explore the correlation structure of the main tree attributes, regression analysis to relate radial and height increment and dendroclimatic analysis to assess the influence of climate on tree growth and IADF formation.Most black pine trees were located at high altitude and their structural attributes were similar at the four sites where the pine encroachment process started between 30 and 40 years ago featuring similar germination peaks and growth patterns. Black pine is particularly sensitive to maximum temperatures and IADF occurred in mid-late summer with highest frequency peaks between 2003 and 2004. The pine encroachment process, besides the differences of environmental features and land use histories of the four study sites, appears synchronic and spatially diffused. Consistent tree-growth dynamics and the species adaptation to a warming climate are signals envisaging a possible treeline upward shift.     

Plastic Response of Tracheids in Pinus pinaster in a Water-Limited Environment: Adjusting Lumen Size instead of Wall Thickness

The formation of wood results from cambial activity and its anatomical properties reflect the variability of environmental conditions during the growing season. Recently, it was found that wood density variations in conifers growing under cold-limited environment result from the adjustment of cell wall thickness (CWT) to temperature. Additionally, it is known that intra-annual density fluctuations (IADFs) are formed in response to precipitation after the summer drought. Although IADFs are frequent in Mediterranean conifers no study has yet been conducted to determine if these structures result from the adjustment of lumen diameter (LD) or CWT to soil water availability. Our main objective is to investigate the intra-ring variation of wood anatomical features (LD and CWT) in Pinus pinaster Ait. growing under a water-limited environment. We compared the tracheidograms of LD and CWT for the years 2010–2013 in P. pinaster growing in the west coast of Portugal. Our results suggest a close association between LD and soil moisture content along the growing season, reinforcing the role of water availability in determining tracheid size. Compared with CWT, LD showed a higher intra- and inter-annual variability suggesting its strong adjustment value to variations in water availability. The formation of a latewood IADF appears to be predisposed by higher rates of cell production in spring and triggered by early autumn precipitation. Our findings reinforce the crucial role of water availability on cambial activity and wood formation in Mediterranean conifers, and emphasize the high plasticity of wood anatomical features under Mediterranean climate.     

Habitat matters: The role of spore bank fungi in early seedling establishment of Florida slash pines

This study investigated broad patterns in communities of ectomycorrhizal fungi from three Florida habitats (sandhills, scrub, and pine rocklands) and the ability of spore bank fungi to associate with Pinus elliottii (slash pine) and Pinus densa (south Florida slash pine). Efforts to replant pines in the endangered pine rocklands are vital to the persistence of this habitat, yet little is known about the ectomycorrhizal fungi communities or how they may differ from those in other pine-dominated habitats in Florida. We used high-throughput amplicon sequencing (HTS) to assess baseline fungal communities and greenhouse bioassays to bait ectomycorrhizal fungi using seedlings. HTS soil data recovered 188 ectomycorrhizal species but only a few subsequently colonized the bioassay seedlings. We recovered 21 ectomycorrhizal species on pine seedlings including common spore bank fungi such as Cenococcum, Suillus, and Tuber, but Rhizopogon species were dominant across all sites and habitats. Habitat type and site were significant variables influencing the community composition of the total soil fungal community, soil ectomycorrhizal community, and the fungi found on seedling root tips. However, we found no significant differences between the ectomycorrhizal communities on seedling roots from the two Pinus species.     

Environmental Factors Affecting Productivity of Brown-Headed Nuthatches

Abstract: Understanding the link between habitat use and components of fitness can yield useful insight into the environmental conditions necessary for population maintenance and can help promote effective habitat management. This information is especially important for species that are in decline or otherwise of conservation concern. Populations of brown-headed nuthatches (Sitta pusilla), an obligate cavity nester, have declined throughout their range, primarily due to extensive habitat loss and degradation. To help guide habitat management for this species, we identified habitat features associated with variation in the number of offspring fledged within 2 populations in southern Florida, USA. The most important predictor of productivity was the date on which a nest attempt began, with earlier nests producing more fledglings. The number of large pine (Pinus elliottii var. densa) snags and, to a lesser extent, the number of small pine trees surrounding a nest site were positively associated with productivity. We recommend that land managers in southern Florida focus on providing abundant large pine snags because doing so will increase productivity and also may increase nest-site availability and the percentage of individuals that breed each year. Prescribed burning may be an effective way to increase the abundance of large pine snags; however, land managers should exercise caution when doing so because of the trade-off between snag recruitment and snag consumption that accompanies the use of fire. We lack the data required to predict the fire-return interval that optimizes this trade-off, but until these data are available we recommend increasing the spatial heterogeneity in fire-return interval and lengthening the fire-return interval in some areas to 5-6 years.     

Tree ring anatomy indices of Pinus tabuliformis revealed the shifted dominant climate factor influencing potential hydraulic function in western Qinling Mountains

Trees can adjust xylem anatomical structure related with potential hydraulic functions to cope with climate variability. We therefore need a better understanding of how climate variability constrains wood anatomy and tree radial growth. Pinus tabuliformis dominates natural forests and plantations over the western Qinling Mountains, which is one of the ecologically vulnerable areas in China. Here, we investigated the response of P. tabuliformis tree-ring anatomical structure to climate variability by applying wood anatomy analysis, and evaluated the influences of anatomical traits on potential hydraulic functions and the climate significance of intra-annual density fluctuations (IADFs). We found that with the increasing temperature from spring to summer, the negative effect of temperature on the formation and enlargement of earlywood and transition-wood tracheids was gradually enhanced. However, spring precipitation not only had a direct and positive influence on the formation of earlywood, but also had a delaying impact on the transition-wood cell enlargement. Besides, the smaller earlywood tracheid size of P. tabuliformis could be a substantially characteristic reflecting spring drought. The contribution of lumen diameter on conduit wall reinforcement was dominated in earlywood, while the contribution of cell wall thickness was greater than that of lumen diameter in latewood. The different contributions of anatomical traits on conduit wall reinforcement would further affect the response of potential hydraulic function to climate. IADFs of P. tabuliformis could be a potential indicator to reflect the abnormal summer precipitation events in the western Qinling Mountains. IADFs with strong and weak intensity indicated years with high and low rates of change in mid-summer precipitation, respectively. Future warmer and drier climate in the western Qinling Mountains will likely result in the production of smaller tracheids to ensure hydraulic safety, which means the stronger drought resistant of P. tabuliformis in the future. In this study, we linked the xylem anatomy and potential hydraulics functions with intra-seasonal climate variability in the context of climate warming and drying, and proposed some xylem anatomical indices reflecting potential drought events.     

Tree-ring growth and intra-annual density fluctuations of Pinus pinaster responses to climate: does size matter?

Dendroclimatology generally assumes that climate–growth relationships are age and size independent. However, there is evidence that climate response can be unstable across different age/size classes. In addition, the occurrence of some anatomical features, such as intra-annual density fluctuations (IADFs), is age dependent. The present study investigates whether the climate–growth responses and the occurrence of IADFs in an even-aged stand of Pinus pinaster Ait., growing under Mediterranean climate, are also size-dependent. We randomly selected 60 P. pinaster trees falling within two stem diameter classes: small (<27 cm) and large (>35 cm). Tree rings were crossdated, measured and IADFs identified according to their position within the ring. The residual chronologies of both size classes were strongly correlated, suggesting a common signal. In fact, similar growth–climate relationships were observed in large and small trees. The frequency of IADFs was higher in large than in small trees, suggesting that IADFs were more likely to occur in wider rings of fast-growing trees. In both size classes, most of the IADFs were found in latewood. Latewood IADFs were triggered by the combination of dry June, wet September, and warm December, whereas IADFs located at the end of earlywood were triggered by previous winter precipitation and favorable conditions before summer (high precipitation for large trees and lower temperature for small trees). Our results suggest that IADFs can be a mechanism used at the individual level for adaptation to drought in P. pinaster. The climatic signal of IADFs between earlywood and latewood was mediated by stem size suggesting that future tree-ring studies should include trees stratified by size to better estimate the sensitivity of IADFs to climate.     

Transmission of the Pinewood Nematode, Bursaphelenchus xylophilus,to Slash Pine Trees and Log Bolts by a Cerambycid Beetle,Monochamus titillator, in Florida

Field-collected adults of the southern pine sawyer, Monochamus titillator (F.) (Coleoptera: Cerambycidae), naturally infested with fourth-stage juveniles (dauerlarvae) of the pinewood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer, 1934) Nickle, 1970, were maturation fed on excised shoots of typical slash pine, Pinus elliottii Engelm. var elliottii, for 21 days. During August 1981, a male and female adult beetle were held in a sleeve cage placed on the terminal of a side branch of each of seven replicate, healthy 10-year-old slash pine trees. All seven branch terminals showed evidence of beetle feeding on the bark after 1 week, and pinewood nematodes were present in wood samples taken near these feeding sites. Four of the seven trees showed wilt symptoms in 4-6 weeks and died about 9 weeks after beetle feeding. Pinewood nematodes were recovered from the roots and trunks of the dead trees. Each of seven replicate slash pine log bolts was enclosed in a jar with a pair of the same beetles used in the sleeve cages. After 1 week, wood underlying beetle oviposition sites in the bark of all replicate log bolts was infested with the pinewood nematode.     

Climatic control of intra-annual wood density fluctuations of Pinus pinaster in NW Spain

Tree rings of Pinus pinaster often contain intra-annual density fluctuations (IADFs), which have been attributed to the succession of dry and rainy periods typical of Mediterranean climate, but their formation has not been studied yet under Atlantic climate. We analyzed the occurrence and climatic significance of replicated IADFs in ten monospecific stands in NW Spain. The frequency of IADFs was higher than previously reported for this species under Mediterranean conditions and consistently decreased with increasing elevation. The formation of bands of latewood-like tracheids within the earlywood was favored by dry previous August, cold previous winter and dry April. Bands of earlywood-like tracheids within the early latewood were also favored by low winter temperatures. However, their occurrence was geographically heterogeneous, with two groups of stands being defined by their distances to the shoreline. In coastal stands, cold May–August triggered IADFs formation, while in inland stands their formation was favored by dry May–July. Regional winter temperatures and April water balance were strongly related to the East Atlantic (EA) pattern, which greatly conditioned the occurrence of IADFs in the earlywood and the early latewood. By contrast, the presence of bands of earlywood-like tracheids in the late latewood was independent of the EA pattern, being strongly related to warm conditions in spring and especially to a wet October. The link between regional climate and the EA pattern strongly controlled the physiological processes that determine intra-annual growth dynamics and short-term cell enlargement of P. pinaster in NW Spain.     

High-resolution climatic analysis of wood anatomical features in Corsican pine from Corsica (France) using latewood tracheid profiles

Key message

We propose a new methodology to identify intra-annual density fluctuations in latewood using cell features and relative radial position within the latewood of pine trees growing on Corsica, France. Climatic forcing of latewood wood anatomical anomalies was analyzed.

Abstract

We analyzed latewood anatomical features from Corsican pine (Pinus nigra ssp. laricio) of high-elevation sites in Corsica (France) derived from digital images of the wood surface. Latewood of each ring during the period 1950–2008 was partitioned into ten equal parts P1–P10. Mean values of the cell parameters cell lumen area (CLA), radial cell width (RCW), radial cell wall thickness (CWT), and modeled latewood density (MLD) were calculated for P1–P10. The cellular profiles for each cell parameter were subjected to principal component analyses. It was possible to quantify macroscopically visible variations of wood anatomy like intra-annual density fluctuations (IADFs) by latewood profiles of different cell parameters. A combination of cell parameter characteristics including their relative radial position within latewood provides a quantification of the cell anatomical variations in an IADF. Individual cell parameter chronologies and principal components of cell parameter profiles were correlated with climate data to determine the climatic forcing on latewood formation. Average cell parameter profiles and deviations from the long-term means are able to describe “normal” and “anomalous” environmental conditions during latewood formation. Cell feature anomalies throughout the latewood during individual years allow the reconstruction of past weather conditions with a high temporal resolution.     

Age-dependent responses of tree-ring growth and intra-annual density fluctuations of Pinus pinaster to Mediterranean climate

Dendrochronology generally assumes that climate–growth relationships are age independent once the biological growth trend has been removed. However, tree physiology, namely, photosynthetic capacity and hydraulic conductivity changes with age. We tested whether the radial-growth response to climate and the intra-annual density fluctuations (IADFs) of Pinus pinaster Ait. varied with age. Trees were sampled in Pinhal de Leiria (Portugal), and were divided in two age classes: young (<65 years old) and old (>115 years old). Earlywood and tree-ring width of young P. pinaster trees were more sensitive to climate influence while the response of latewood width to climate was stronger in old trees. Young trees start the growing season earlier, thus a time window delay occurs between young and old trees during which wood cells of young trees integrate environmental signals. Young trees usually have a longer growing season and respond faster to climate conditions, thus young P. pinaster trees presented a higher frequency of IADFs compared with old trees. Most of the IADFs were located in latewood and were positively correlated to autumn precipitation. The radial-growth response of P. pinaster to climate and the IADFs frequency were age dependent. The use of trees with different age to create a tree-ring chronology for climate studies can increase the resolution of climatic signals. Age-dependent responses to climate can also give important clues to predict how young and old trees react to climate change.     

Drought alters timing, quantity, and quality of wood formation in Scots pine

Drought has been frequently discussed as a trigger for forest decline. Today, large-scale Scots pine decline is observed in many dry inner-Alpine valleys, with drought discussed as the main causative factor. This study aimed to analyse the impact of drought on wood formation and wood structure. To study tree growth under contrasting water supply, an irrigation experiment was installed in a mature Scots pine (Pinus sylvestris L.) forest at a xeric site in a dry inner-Alpine valley. Inter- and intra-annual radial increments as well as intra-annual variations in wood structure of pine trees were studied. It was found that non-irrigated trees had a noticeably shorter period of wood formation and showed a significantly lower increment. The water conduction cells were significantly enlarged and had significantly thinner cell walls compared with irrigated trees. It is concluded that pine trees under drought stress build a more effective water-conducting system (larger tracheids) at the cost of a probably higher vulnerability to cavitation (larger tracheids with thinner cell walls) but without losing their capability to recover. The significant shortening of the growth period in control trees indicated that the period where wood formation actually takes place can be much shorter under drought than the 'potential' period, meaning the phenological growth period.     

Effects of Hurricane Andrew on stands of slash pine (Pinus elliottii var. densa) in the everglades region of south Florida (USA)

Few hurricanes affect intact stands of subtropical pines. We examined effects of winds in the eyewalls of Hurricane Andrew, where wind speeds were >200 km h^–1, on all remaining large mainland stands of Pinus elliottii var. densa (south Florida slash pine) on limestone outcroppings (rocklands) in the everglades region of southern Florida. We measured densities and sizes of trees and assessed damage and mortality in plots in old-growth stands in the Lostman's Pines (LOP) region of Big Cypress National Preserve and in second-growth stands in the Pines West (PIW) and Long Pine Key (LPK) regions of Everglades National Park. We also examined age-size relationships using sections from trees killed by the hurricane in LOP and LPK. We used the data to predict effects of recurrent hurricanes on the structure and dynamics of the old-growth stand and to compare effects of hurricanes on old- and second-growth stands.Slash pine was resistant to hurricane winds. Most trees in stands (68–76%) were not severely damaged; mortality in the three regions averaged 17–25% shortly after the hurricane and 3–7% during the following year. Mortality was positively associated with tree size; mean tree sizes decreased and size-selective thinning occurred in all stands. Nonetheless, local mortality ranged from 3–4% to 50–60% among plots in all stands. Such local variation in mortality resulted from clustering of large trees, especially in old-growth stands, and from microbursts during the hurricane, which affected all stands. Recurrent, intense hurricanes are predicted to kill larger trees, slowly opening new patches and increasing sizes of extant patches, thus resulting in almost continual presence of openings suitable for recruitment in old-growth stands. Age-size relationships also indicated that large trees in old-growth stands may survive 2–3 centuries. The combination of frequent openings and wind resistance of large trees is predicted to result in old-growth stands that are highly uneven aged, with trees locally distributed in similar-aged patches. The extent to which such stands deviate from demographic equilibrium, as well as turnover rates within stands, are likely to increase as the frequency of recurrent, intense hurricanes increases.Damage and mortality differed in old- and second-growth stands. Large trees were more, but small trees less likely to be damaged in old- than second-growth stands. In contrast, mortality was significantly lower in old- (LOP: 16.9% ± 3.1 [mean ± s.e.]) than second-growth stands (PIW: 22.5% ± 2.0; LPK: 25.2% ± 2.7). Total hurricane-related mortality was 30–60% higher in second- than old-growth stands. Size class structure, more uneven in old- than second growth stands prior to the hurricane, diverged even more afterwards. Hurricane Andrew removed     

Protocylindrocorpus dendrophilus n. sp. (Nematoda: Cylindrocorpidae) Associated with Pine Wood Borings

Protocylindrocorpus dendrophilus n. sp. is described from xylem samples taken from beetle infested slash pine (Pinus elliottii Engelmann var. elliottii) in Central Louisiana. It is similar to P. goodeyi (Rühm) Paramonov, but differs by the possession of a protuberant and more posteriorly located vulva and in the position of the caudal papillae. Morphometrics of the male and female are presented.     

Localized cooling of stems induces latewood formation and cambial dormancy during seasons of active cambium in conifers

Background and Aims In temperate regions, trees undergo annual cycles of cambial growth, with periods of cambial activity and dormancy. Environmental factors might regulate the cambial growth, as well as the development of cambial derivatives. We investigated the effects of low temperature by localized cooling on cambial activity and latewood formation in two conifers, Chamaecyparis obtusa and Cryptomeria japonica.Methods A plastic rubber tube that contained cooled water was wrapped around a 30-cm-wide portion of the main stem of Chamaecyparis obtusa and Cryptomeria japonica trees during seasons of active cambium. Small blocks were collected from both cooled and non-cooled control portions of the stems for sequential observations of cambial activity and for anatomical measurements of cell morphology by light microscopy and image analysis.Key Results The effect of localized cooling was first observed on differentiating tracheids. Tracheids narrow in diameter and with significantly decreased cambial activity were evident 5 weeks after the start of cooling in these stems. Eight weeks after the start of cooling, tracheids with clearly diminished diameters and thickened cell walls were observed in these stems. Thus, localized low temperature induced narrow diameters and obvious thickening of secondary cell walls of tracheids, which were identified as latewood tracheids. Two months after the cessation of cooling, a false annual ring was observed and cambium became active again and produced new tracheids. In Cryptomeria japonica, cambial activity ceased earlier in locally cooled portions of stems than in non-cooled stems, indicating that the cambium had entered dormancy sooner in the cooled stems.Conclusions Artificial cooling of stems induced latewood formation and cessation of cambial activity, indicating that cambium and its derivatives can respond directly to changes in temperature. A decrease in the temperature of the stem is a critical factor in the control of cambial activity and xylem differentiation in trees.     

Does insect induced defoliation affect anatomical structure of oak wood?

We counted the intra-annual density fluctuations (IADFs) of oak (Quercus robur) tree rings sampled in a deciduous broadleaf forest near Kozelsk (Kaluga region) in the Ugra National Park, Central Russia. Three sites in the same forest massif were sampled. We also sampled ash (Fraxinus excelsior) trees in one of these sites as a non-host species for the identification of insect outbreaks. In total, 49 oak and 21 ash trees were sampled and analyses were performed for the period 1878–2015. Within the selected time framework, we observed numerous cases with: 1) high percentage of IADFs, 2) decreased oak tree ring widths compared to that of ashes, 3) considerable quantity of oak trees with abrupt growth changes (AGC), and 4) statistically significant differences in counts of IADFs and AGC between the three sampling sites. These traits were characteristic for several consecutive years, and we interpret these as evidence of the insect herbivory causing growth interruptions during the period of the oak leaf expansion. Other external stress factors including summer droughts and late spring frosts can intensify IADFs manifestations during insect outbreaks, but did not affect oak growth strongly enough to cause growth interruptions without insect interference.     

Transpecific microsatellites for hard pines

Microsatellites are difficult to recover from large plant genomes so cross-specific utilisation is an important source of markers. Fifty microsatellites were tested for cross-specific amplification and polymorphism to two New World hard pine species, slash pine (Pinus elliottii var. elliottii) and Caribbean pine (P. caribaea var. hondurensis). Twenty-nine (58%) markers amplified in both hard pine species, and 23 of these 29 were polymorphic. Soft pine (subgenus Strobus) microsatellite markers did amplify, but none were polymorphic. Pinus elliottii var. elliottii and P. caribaea var. hondurensis showed mutational changes in the flanking regions and the repeat motif that were informative for Pinus spp. phylogenetic relationships. Most allele length variation could be attributed to variability in repeat unit number. There was no evidence for ascertainment bias.