Width Chronologies Research Articles

Up to 400‐year‐old Rhododendron shrubs on the southeastern Tibetan Plateau: prospects for shrub‐based dendrochronology

In harsh and treeless environments, shrubs constitute the dominant growth form of woody plants, thus offering the opportunity to extend dendrochronological networks beyond the uppermost and northernmost distribution limits of trees. However, shrub‐based dendrochronology has so far resulted in only a few long and climate‐responsive ring‐width chronologies at such stressful sites, particularly above the alpine tree line. A previous study on an alpine Rhododendron shrub species resulted in <80‐year‐long ring‐width chronologies. Here, we collected Rhododendron aganniphum var. schizopeplum stems from elevations between 4000 and 4500 m a.s.l. on the SE Tibetan Plateau and built six tree‐ring width chronologies. One of them is 401 years long and well replicated from AD 1670 to 2011 (EPS>0.85), thus representing the longest shrub chronology available to date. A principal component analysis (PCA) converted the total variability of all six site chronologies into PCs. Then, the six site chronologies and the PC1, accounting for 65.9% of the total variance of the tree‐ring width, were correlated with time series of monthly climate data. Based on this, the year‐to‐year variability of the ring‐width indices was positively correlated with July temperature, which thus turned out to be the dominant factor controlling growth. Accordingly, such long shrub‐ring chronologies may act as climatic and ecological proxies in treeless environments of the Tibetan Plateau.

How do climate and topography influence the greening of the forest‐tundra ecotone in northern Québec? A dendrochronological analysis ofBetula glandulosa

SummaryNDVIanalysis and repeated aerial photographs have revealed significant shrub expansion in many subarctic regions. While the recent increase in temperature is usually considered to be the main driver of this phenomenon at regional scales, very little is known about the local heterogeneity of shrub responses across the landscape.In this study, we aim to identify the climatic factors controlling the growth of the largely distributed shrub speciesBetula glandulosain three types of environments (terrace, hilltop and snowbed). We also aim to evaluate the relationship betweenB. glandulosagrowth and theNDVIdata for the Boniface River region, in north‐western Québec, where the study took place.In the field, we harvested 180B. glandulosaindividuals (20 per site, 3 sites per type of environment). We constructed specific growth‐ring width chronologies and mean axial growth rate chronologies for each site and used them for dendroclimatic analysis (response functions). We also used linear regressions to evaluate the relative influence of dwarf birch growth on theNDVItrend.We found a sharp increase inB. glandulosaradial growth in the 1990s followed by a sharp decreasing trend from 2002 on terraces and hilltops, while growth remained high in snowbeds.Betula glandulosagrowth was positively correlated with summer temperatures on terraces and hilltops, whereas winter precipitation promoted growth on snowbeds. TheNDVItrend was largely correlated toB. glandulosagrowth on terraces and hilltops for the period between 1986 and 2002 (71–80% explained variance).Synthesis. Our results suggest that topography plays a major role inB. glandulosagrowth and therefore in shrub community dynamics. Because terraces and hilltops represent 70% of the land surface, the sharpB. glandulosagrowth increase at these sites promoted an important overall expansion of the shrub community in the region. However, the decline inB. glandulosagrowth observed after 2002 suggests that the expansion could be slowed down in the near future, therefore limiting shrub growth contribution to the regionalNDVIsignal.

Convergence in drought stress, but a divergence of climatic drivers across a latitudinal gradient in a temperate broadleaf forest

AbstractAimInformation about climate stressors on tree growth is needed in order to assess the impacts of global change on forest ecosystems. Broad‐scale patterns of climatic limitations on tree growth remain poorly described across eastern North American deciduous forests. We examined the response of broadleaf tree species to climate in relation to their taxonomy, functional traits and geographical location.LocationEastern North America (32–45° N; 70–88° W).MethodsWe used a network of 86 tree‐ring width chronologies from eight species that cover a wide range of ecological and climatic conditions. Species were analysed individually or combined according to taxa and wood anatomical functional traits. We identified climate stressors through correlations between growth and climate (from 1916 to 1996). We also explored patterns in the climate responses of these species with two clustering techniques.ResultsWe found strong correlations between water availability and growth for all species. With few exceptions, this drought stress was independent of taxonomy or wood anatomical functional group. Depending on latitude, however, different climatic drivers governed this common drought response. In the cool, northern part of our network, forest growth was most strongly limited by precipitation variability, whereas maximum temperature was a stronger limiting factor than precipitation in the wetter and warmer southern parts.Main conclusionsOur study highlights the sensitivity of broadleaf temperate forests to drought stress at annual to decadal scales, with few species‐specific differences. The roles of temperature and precipitation on drought‐sensitivity differ at opposing ends of our subcontinental‐scale network. The impact of future environmental changes on these forests will ultimately depend on the balance between temperature and precipitation changes across this latitudinal gradient.

Intra-annual dendroclimatic reconstruction for northern British Columbia, Canada, using wood properties

Analyses of tree-ring wood properties combined with an understanding of tree physiology provided detailed intra-annual insights into historical and seasonal climate phenomena in sub-boreal forests of northern British Columbia. This study investigated historical climate trends in northern British Columbia, Canada, through the use of tree-ring proxies, and established a means of reconstructing intra-annual climate patterns from wood density, fibre properties and tree-ring width data. Specific attention was given to investigating how dendroclimatological analyses of intra-ring wood and fibre properties could be interpreted to improve the strength of proxy climate records. Trees were sampled at six sites in northern British Columbia. Spruce trees were collected from the Smithers area, whilst Douglas-fir trees were sampled at the northern latitudinal extent of their range near Babine and Francois Lakes, and at a precipitation-limited site near Valemount. Wood cores were analysed by Windendro® software with an ITRAX scanning densitometer, and by the SilviScan system located at the Australian Commonwealth Scientific and Research Organization. A mean June temperature proxy record dating to 1805 and a July–August mean temperature proxy record for Smithers extending from 1791 to 2006 were constructed from spruce ring width and maximum density chronologies. Douglas-fir ring width, spruce minimum density, and Douglas-fir maximum cell-wall thickness chronologies were used to reconstruct a May–June precipitation record extending from 1820 to 2006, and a July–August total precipitation record for Fort St. James that extends from 1912 to 2006. The results of the study demonstrate that a combination of multivariate and single-variate analyses provide detailed insights into seasonal radial growth characteristics. Tree physiological responses to climate at different times throughout the growing season, and temperature and precipitation fluctuations over the historical record are discussed.

Dendroclimatic Reconstruction of Summer Temperatures in Irik Valley, Mount Elbrus (Greater Caucasus)

Recent evidence suggests an acceleration of glacier retreat in Greater Caucasus after 1980. For the same period a significant summer temperature warming trend and little or no change in precipitation variation have been observed. In this paper we seek to find similar past climatic conditions using a dendroclimatic reconstruction of summer temperatures from upper treeline sites after the Little Ice Age (LIA). Dendroclimatological sampling of Scots pine (Pinus sylvestris) has been made in Irik Valley, near Elbrus glacier, and a tree-ring width (TRW) chronology has been used to reconstruct May – August (MJJA) temperatures back to 1830. Three warm periods were identified in the MJJA temperatures reconstructed data (1830 - 1900), but we cannot appreciate if they had the same intensity as the recent warm period

The climate of Myanmar: evidence for effects of the Pacific Decadal Oscillation

ABSTRACTWe show evidence for the influence of the Pacific Decadal Oscillation (PDO) on Myanmar's monsoonal hydroclimate using both instrumental and 20th century reanalysis data, and a tree‐ring width chronology from Myanmar's central Dry Zone. The ‘regime shifts’ identified in the instrumental PDO for the past century are clearly evident in the Myanmar teak. The teak record and PDO index correlate most significantly and positively during December–May, at r = 0.41 (0.002, n = 109). We generated composite climate anomalies for southern Asia and adjacent ocean areas during negative and positive PDO phases and above/below average teak growth for the May–September wet monsoon season. They show that negative (positive) PDO phases correspond to dry (wet) conditions, due to reduced (enhanced) moisture flux into central Myanmar. Multitaper Method (MTM) and Singular Spectrum Analysis (SSA) spectral analyses reveal considerable multidecadal variability over the past several centuries of the teak chronology, consistent with the PDO.

Spatial and temporal stability of the climatic signal in northern Fennoscandian pine tree‐ring width and maximum density

The spatial and temporal stability of the climatic signal in pine tree‐ring width and maximum density is examined using data from four sites in northern Sweden and Finland. Moving‐window multiple linear regression, using monthly and daily climate data, indicates that ring widths at all sites have been strongly controlled by July temperatures throughout the past century. The relationship between maximum density and temperature is stronger but much less stable across both space and time. Shifts in the hottest part of the summer do not explain large shifts in the period most strongly influencing density. It is concluded that palaeoclimate reconstructions based on northern Fennoscandian pine tree‐ring width chronologies should be restricted to the temperature of midsummer (July), whereas maximum density should be used to reconstruct the temperature of a longer growth season (June to August). They thus provide different and complementary palaeoclimate signals. At all four sites, the correlation between maximum density and June to August mean temperature is lowest in the latter half of the 20th century, but split sample tests with strong verification statistics (RE and CE) show that this represents a quantitative change in the strength of the correlation with climate, rather than a qualitative change in the nature of that relationship, and thus does not invalidate climate reconstructions.

Testing for tree‐ring divergence in the European Alps

AbstractEvidence for reduced sensitivity of tree growth to temperature has been reported from multiple forests along the high northern latitudes. This alleged circumpolar phenomenon described the apparent inability of temperature‐sensitive tree‐ring width and density chronologies to parallel increasing instrumental temperature measurements since the mid‐20th century. In addition to such low‐frequency trend offset, the inability of formerly temperature‐sensitive tree growth to reflect high‐frequency temperature signals in a warming world is indicated at some boreal sites, mainly in Alaska, the Yukon and Siberia. Here, we refer to both of these findings as the ‘divergence problem’ (DP), with their causes and scale being debated. If DP is widespread and the result of climatic forcing, the overall reliability of tree‐ring‐based temperature reconstructions should be questioned. Testing for DP benefits from well‐replicated tree‐ring and instrumental data spanning from the 19th to the 21st century. Here, we present a network of 124 larch and spruce sites across the European Alpine arc. Tree‐ring width chronologies from 40 larch and 24 spruce sites were selected based on their correlation with early (1864–1933) instrumental temperatures to assess their ability of tracking recent (1934–2003) temperature variations. After the tree‐ring series of both species were detrended in a manner that allows low‐frequency variations to be preserved and scaled against summer temperatures, no unusual late 20th century DP is found. Independent tree‐ring width and density evidence for unprecedented late 20th century temperatures with respect to the past millennium further reinforces our results.

Climate increases regional tree‐growth variability in Iberian pine forests

AbstractTree populations located at the geographical distribution limit of the species may provide valuable information about tree‐growth response to changes on climatic conditions. We established nine Pinus nigra, 12 P. sylvestris and 17 P. uncinata tree‐ring width chronologies along the eastern and northern Iberian Peninsula, where these species are found at the edge of their natural range. Tree‐growth variability was analyzed using principal component analysis (PCA) for the period 1885–1992. Despite the diversity of species, habitats and climatic regimes, a common macroclimatic signal expressed by the first principal component (PC1) was found. Moreover, considering the PC1 scores as a regional chronology, significant relations were established with Spanish meteorological data. The shared variance held by the tree chronologies, the frequency of narrow rings and the interannual growth variability (sensitivity) increased markedly during the studied period. This shows an enhancement of growth synchrony among forests indicating that climate might have become more limiting to growth. Noticeably, an upward abrupt shift in common variability at the end of the first half of the 20th century was detected. On the other hand, moving‐interval response functions showed a change in the growth–climate relationships during the same period. The relationship between growth and late summer/autumn temperatures of the year before growth (August–September, negative correlation, and November, positive correlation) became stronger. Hence, water stress increase during late summer previous to tree growth could be linked to the larger growth synchrony among sites, suggesting that climate was driving the growth pattern changes. This agrees with the upward trend in temperature observed in these months. Moreover, the higher occurrence of extreme years and the sensitivity increase in the second half of the 20th century were in agreement with an increment in precipitation variability during the growing period. Precipitation variability was positively related to tree‐growth variability, but negatively to radial growth. In conclusion, a change in tree‐growth pattern and in the climatic response of the studied forests was detected since the mid‐20th century and linked to an increase in water stress. These temporal trends were in agreement with the observed increase in warmer conditions and in precipitation variability.

Spatial and temporal variation in Nothofagus pumilio growth at tree line along its latitudinal range (35°40′–55° S) in the Chilean Andes

AbstractAim To identify the dominant spatial and temporal patterns of Nothofagus pumilio radial growth over its entire latitudinal range in Chile, and to find how these patterns relate to temperature and precipitation variation from instrumental records.Location This study comprises 48 tree line or high elevation N. pumilio sites in the Chilean Andes between 35° 36′ and 55° S. Nothofagus pumilio is a deciduous tree species that dominates the upper tree line of the Chilean and Argentinean Andes in this latitudinal range.Methods At each of the sampled sites, two cores from 15 to 40 living trees were collected using increment borers. Cores were processed, tree rings were measured and cross‐dated, using standard dendrochronological procedures. Radii from nearby sites were grouped into 13 study regions. A composite tree‐ring width chronology was developed for each region in order to capture and integrate the common growth patterns. For the identification of the dominant patterns of growth, as well as temperature and precipitation variation, we used principal components (PCs) analysis. Correlation analysis was used for the study of the relationship of N. pumilio tree‐ring growth with temperature and precipitation records.Results Nothofagus pumilio tree line elevation is 1600 m in the northernmost region and gradually decreases to 400 m in the southernmost region. Despite local differences along the transect, the decrease in tree line elevation is fairly constant, averaging c. 60 m per degree of latitude (111 km). Tree growth at the northernmost regions shows a positive correlation with annual precipitation (PC1‐prec) and negative correlation with mean annual temperature (PC2‐temp), under a Mediterranean‐type climate where water availability is a major limiting factor. Conversely, tree growth is positively correlated with mean annual temperature (PC1‐temp) in the southern portion of the gradient, under a relatively cooler climate with little seasonality in precipitation.Main conclusions Our findings indicate that temperature has a spatially larger control of N. pumilio growth than precipitation, as indicated by a significant (P < 0.05) either positive or negative correlation of tree growth and PC1‐temp and/or PC2‐temp for nine of the 13 regional chronologies (69.2% of the total), whereas precipitation is significantly correlated with only two chronologies (15.4% of the total). Temporal patterns of N. pumilio tree growth reflected in PC1‐growth for the period between 1778 and 1996 indicate an increasing trend with above the mean values after 1963, showing high loadings in the southern part of the gradient. This trend may be explained by a well‐documented increase in temperature in southern Patagonia. Ongoing and future research on N. pumilio growth patterns and their relationship to climate covering the Chilean and Argentinean Andes will improve the understanding of long‐term climate fluctuations of the last three to four centuries, and their relationship to global change at a wide range of spatial and temporal scales.

Summer temperature variability in central scandinavia during the last 3600 years

ABSTRACT. A Scots pine (Pinus sylvestris L.) tree‐ring width chronology from Jämtland, in the central Scandinavian Mountains, built from living and sub‐fossil wood, covering the period 1632 BC to AD 2002, with a minor gap during AD 887–907, is presented. This is the first multi‐millennial tree‐ring chronology from the central parts of Fennoscandia. Pine growth in this tree line environment is mainly limited by summer temperatures, and hence the record can be viewed as a temperature proxy. Using the regional curve standardization (RCS) technique, pine‐growth variability on short and long time scales was retained and subsequently summer (June–August) temperatures were reconstructed yielding information on temperature variability during the last 3600 years. Several periods with anomalously warm or cold summers were found: 450–550 BC (warm), AD 300–400 (cold), AD 900–1000 (the Medieval Warm Period, warm) and AD 1550–1900 (Little Ice Age, cold). The coldest period was encountered in the fourth century AD and the warmest period 450 to 550 BC. However, the magnitude of these anomalies is uncertain since the replication of trees in the Jämtland record is low during those periods. The twentieth century warming does not stand out as an anomalous feature in the last 3600 years. Two multi‐millennial tree‐ring chronologies from Swedish and Finnish Lapland, which have previously been used as summer temperature proxies, agree well with the Jämtland record, indicating that the latter is a good proxy of local, but also regional, summer temperature variability.

Summer moisture variability in east central sweden since the mid‐eighteenth century recorded in tree rings

To make predictions of future climate it is necessary to understand the past climate—temperature as well as precipitation. While a wealth of temperature proxies exist from northern latitudes, there is still a lack of information about past precipitation variability. Here we present a 300‐year‐long tree‐ring width chronology from xeric‐site Scots pines (Pinus sylvestris L.) in Tyresta National Park, east central Sweden. Tree‐ring widths were compared to the long observed temperature and precipitation records from Stockholm during 1786–2000. Analyses of the climate/growth relationship showed that, in general, May–June precipitation had a dominating influence on pine growth. However, during dry periods, negative responses to June–July temperature were stronger, especially evident in the late nineteenth century. Periods of below‐average growth were associated with dry conditions in May–June, but occasionally periods of wet and cool summers also produced narrow rings. Periods of above‐average growth were linked to wet, but sporadically also cool and dry, early summers. The years between 1815 and 1833 appear to be particularly dry in the 300‐year context. Since growth anomalies are found in other Swedish drought‐sensitive tree‐ring chronologies during this period, it is likely that this dry period had a regional extent. This is the first tree‐ring chronology from southern Sweden that provides multi‐century information of past summer drought and moisture variability with high resolution and the study will add important information regarding past climate variability in southern Sweden.

Effects of climate on the radial growth of tree species in the upper and lower distribution limits of an altitudinal ecotone on Mount Norikura, central Japan

Tree‐ring width chronologies were developed for Abies veitchii, Betula ermanii and Betula platyphylla var. japonica in their altitudinal ecotone (approximately 1600 m a.s.l.) on Mount Norikura, central Japan, to determine what climatic conditions affect the growth of tree species in the upper and lower distribution limits of an altitudinal ecotone. This altitude was the lower distribution limit for A. veitchii and B. ermanii in the subalpine zone, and was the upper distribution limit for B. platyphylla var. japonica in the montane zone on Mount Norikura. Tree‐ring widths of the two Betula species and A. veitchii were positively correlated with the August precipitation of the current and previous years, respectively. Precipitation in August (the hottest month) was reduced compared with other months during summer. Tree‐ring width of B. platyphylla var. japonica showed no correlation with temperatures in any month in its upper distribution limit. In contrast, tree‐ring widths of B. ermanii and A. veitchii were negatively correlated with the August temperatures of the current and previous years, respectively, at the lower distribution limit of these species. Therefore, the two Betula species and A. veitchii responded to climatic conditions of the current and previous years, respectively. The present study also suggests that a water deficit in August reduces growth of these three species in this altitudinal ecotone, irrespective of the upper or lower distribution limits, and that a high August temperature is more detrimental to the growth of A. veitchii and B. ermanii in their lower distribution limits. Thus, the three species with different altitudinal distributions examined in the present study responded differently to climatic conditions in this altitudinal ecotone on Mount Norikura.

Tree-ring width and density data around the Northern Hemisphere: Part 1, local and regional climate signals

A detailed description is presented of the statistical patterns of climate forcing of tree growth (annual maximum latewood density and ring-width time series), across a network of 387 specially selected conifer sites that circle the extra-tropical Northern Hemisphere. The in‘ uence of summer temperature dominates growth. A mean April–September response is optimum for describing the major forcing signal over the whole densito-metric network, though a shorter June–July season is more relevant in central and eastern Siberia. The ring- width chronologies also have a shorter optimum (June–August) seasonal signal, but this is much weaker than the density signal. The association between tree-ring density and precipitation variability (as measured by partial correlations to account for the correlation between temperature and precipitation) is considerably weaker than with temperature. The ring-width response to precipitation is dominated by ‘noise’ and local site in‘ uences, though a negative response to winter precipitation in northern Siberia is consistent with the suggestion of an in‘ uence of delayed snowmelt. Average correlations with winter temperatures are small for all regions and correlations with annual temperatures are positive only because of the strong link with summer temperatures. Reconstructions of summer temperature based on composite regional density chronologies for nine areas are presented. Five regions (northwestern North America, NWNA; eastern and central Canada, ECCA; northern Europe, NEUR; northern Siberia, NSIB; and eastern Siberia, ESIB) constitute an arbitrary ‘northern’ division of the network, while the four other regions (western North America, WNA; southern Europe, SEUR; central Asia, CAS; and the Tibetan Plateau, TIBP) make up the ‘southern’ part. We also present two larger composite regional reconstructions comprising the data from the five higher-latitude (HILAT) and four lower-latitude (LOLAT) areas respectively; and a single series made up of data from all regions (ALL), which is highly correlated with Northern Hemisphere mean summer temperature. We calculate time-dependent uncertainty ranges for each of these reconstructions, though they are not intended to represent long timescales of tempera ture variability (>100 years) because the technique used to assemble the site chronologies precludes this. Finally, we examine in more detail the reduced sensitivity in the tree-growth data to decadal-timescale summer-temperature trends during the last 50 years, identified in earlier published work.

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.

Climatic and anthropogenic influences on radial growth of scots pine at hanvedsmossen, a raised peat bog, in south central sweden

Past studies of the climatic influence on tree growth at peat bogs in northern latitudes have shown weak correlation between annual tree‐ring widths and climatic parameters during the growing season. At Hanvedsmossen, a raised peat bog in south central Sweden, tree‐ring width chronologies from one drained and one undrained growth site, as well as one dry site outside the bog, were compared to meteorological records. Low temperatures, which means less evaporation, as well as high precipitation appear to be inhibiting pine growth at the undisturbed bog site as the trees are sensitive to changes in the local water table. Drainage causes an instant increase in annual tree growth for approximately 10 years. If draining is maintained, the response to climate of the pines resembles that of pines growing on mineral soils. The variance in annual tree‐ring growth explained by temperature/precipitation or both was low for the entire lengths of all chronologies, but high for some analysed subperiods; the significant months changed with time. The reason for this seems to be that pines at Hanvedsmossen are growing in a region where precipitation and temperature are less limiting to tree growth than at higher and lower latitudes.

Dendroclimatic reconstruction of summer precipitation at Srinagar, Kashmir, India, since the late-eighteenth century

The extensive coniferous forests of the western Himalayas provide great potential for dendroclimatic research. Abies, Cedrus, Picea and Pinus are the main tree genera of the region, consisting of many old and living trees. The annual growth-ring patterns of these trees, which can be precisely dated, contain valuable high-resolution information on climate variability over the past few centuries. This paper presents an analysis of the ring-width data of Abies pindrow and Picea smithiana based on samples collected from forest sites around Pahalgam in the Kashmir Valley in 1982. The non- climatic variations have been filtered out of the raw ring-width series using a cubic spline smoothing, and ring-width index series have been obtained. The mean ring-width index chronologies have been prepared by averaging the indices of 13 samples for P. smithiana and eight samples for A. pindrow. The maximum lengths of mean ring-width index chronologies are 208 years (1775-1982) for P. smithiana and 371 years (1612-1982) for A. pindrow. Response functions have been developed using the instrumental record of monthly mean temperature and rainfall at Srinagar during the period 1893-1982. Both ring- width chronologies indicate a significant negative response to summer temperature and a significant positive relationship with summer precipitation. Calibration and verification analysis has been carried out for different combinations of months using a multiple species ring-series network and the summer precipitation at Srinagar has been reconstructed back to the eighteenth century.

A method for studying dead bole dynamics in Pinus contorta var. latifolia ‐ Picea engelmannii forests

Rates of decomposition were determined for the boles of Pinus contorta var. latifolia Engelm. and Picea engelmannii Parry ex. Engelm. in five lower subalpine forest stands in the Southern Canadian Rocky Mountains. Stands ranged in age from 58 to 222 yr since last fire. The date of death of standing dead and fallen boles was determined by cross‐dating their ring‐width patterns to stand master ring‐ width chronologies. Boles could be dated which had been dead for up to 35 years in a 58‐yr old stand and 100 yr in a 222‐yr old stand.An empirical relationship between mass density and diameter of live trees was used to predict the mass density at death for trees already dead. The falling rate of dead standing boles was estimated from the dead bole's time of death and whether it was standing or on the ground at the time of observation. The falling rates for both Pinus contorta and Picea engelmannii ranged from 0.020 to 0.064/yr falling with most stands in the 0.050 range. No effect of size was found on the falling rate probably as a result of the small size of the boles (< 20 cm). Because of their dry condition standing dead boles do not decompose.An equation was developed which estimates the time a dead bole has been on the ground, given that it would have stood for some time before falling over and been subject to little decomposition during this time. Decomposition rates, using a negative exponential model, gave only marginally better r2 than linear models. Pinus contorta had exponential decay rates from 0.0299 and 0.0171 mass density loss/yr for the most recent 15 and 25 yr in stands 58 yr old, to 0.0045 and 0.0035 mass loss/yr for the most recent 65 and 80 yr in stands 215 and 222 yr old. Picea engelmannii had exponential decay rates of 0.0054 and 0.0025 mass loss/yr for the most recent 20 and 65 yr in stands 99 and 215 yr old.