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Summary 1. Our goal was to determine the relationships among ecophysiological, whole-plant and ecosystem traits of a wide variety of grassland species grown under field conditions in the long term. We measured 87 traits for 33 species (32 perennial, one annual) grown in monoculture for 5 years on sandy soils, and determined the relationship among traits and their correspondence with current functional classifications. 2. Among non-legumes, species that produced and maintained large amounts of biomass had tough, low-activity leaves and roots, high root : shoot ratios, and low extractable inorganic nitrogen and N mineralization in their soils. The set of correlations among the functional traits of fine roots for non-legumes parallels the set of correlations for leaf functional traits. Low-N species maintained greater biomass than highN species, more by producing tissues with low N concentrations and greater longevity than by acquiring more N. Greater relative production below ground, and the production of long-lived below-ground structures, were both important in determining the high root : shoot ratio of species. 3. For legumes, N 2 fixation not only led to greater above-ground biomass production, but also was associated with low fine root production; greater relative production of stem biomass; and accelerated ecosystem N cycling compared to non-legumes. 4. The measured traits, as condensed via principal components analysis, differentiated the 32 species into groups that corresponded with a common grassland functional classification scheme (C 3 grasses, C 4 grasses, forbs, legumes, woody species) as well as an alternative, continuous approach. For all traits, species can be arrayed well along two continuous axes. The first axis separates cool-season and warm-season legumes; the second low-N and high-N non-legumes. 5. These continuous classifications show the generality of the two strategies for dealing with low nitrogen availability (N 2 fixation and the low-N suite of traits) and extends the strategies to span organ-level traits to ecosystem processes including roots, whole-plant patterns of productivity, and nutrient cycling. The correlations of traits among species will also be useful in predicting a large number of important parameters associated with plant growth from the measurement of a few, key traits.

1. There are conflicting reports concerning the adaptive features of tree populations originating from cold, high-altitude environments. We hypothesize that such trees will possess adaptive features that will be demonstrated in a common environment, such as elevated rates of net CO2 exchange, elevated needle nitrogen concentration and high proportional biomass allocation to roots. To test this hypothesis we measured tree and seed properties of 54 populations of Norway spruce [Picea abies (L.) Karst.] located along eight altitudinal transects (from c.600 to 1500m) in southern Poland. We also measured growth, biomass partitioning, net photosynthetic capacity (Amax), needle dark respiration (RS) and carbohydrate, nitrogen (N) and chlorophyll concentration of seedlings originating from these populations grown for 2 to 7 years in a common garden at 150m elevation. Measured in situ along the elevational transects, there were linear declines in seed mass, average d.b.h. and height growth increment of seed trees with increased altitude or lower mean annual temperature. 2. In the common garden, the Norway spruce populations from colder, high-altitude habitats had higher N concentration in needles than those from low altitudes. Both Amax and needle RS increased with altitude of seed origin and were significantly related to needle N concentration. High-altitude populations also had higher concentrations of chlorophyll and carotene than those from low elevations. Despite higher photosynthetic rates in high-altitude populations, seedling height and dry mass in the common garden declined with altitude of seed origin. Proportional dry mass partitioning to roots nearly doubled with increasing altitude of origin, while the length of the shoot-growth period was reduced. The high respiration rates, high allocation to roots and reduced shoot-growth period are probably responsible for the low growth rate potential of high-altitude populations, more than offsetting their higher photosynthetic rates. 3. The results of this study showed that Norway spruce populations from cold mountain environments are characterized by several potentially adaptive features. Because these were similar to conifer population responses along a latitudinal gradient of origin, they are probably driven by climate. These climate-driven differences were common to all transects: for a given altitude or mean annual temperature, plant traits were independent of mountain range of origin. However, populations originating from cold high-elevation sites often differed per unit change in altitude or mean annual temperature more than did low elevation populations. The scaling of nitrogen, CO2 exchange and biomass and allocation patterns may be useful in modelling Norway spruce response on montane forest ecosystems under changing environments.

1. To test several hypotheses about acclimation and adaptation of photosynthesis and respiration to differing light conditions, we investigated the interspecific relationships between leaf and root metabolism, chemistry and morphology in high and low light conditions for young seedlings of nine boreal tree species that differ in relative growth rate (RGR). 2. Light-saturated net photosynthesis (Asat), whole-plant nitrogen (N) uptake rates, leaf and root respiration and morphology, and RGR all varied in parallel among the nine species when grown in both 5% and 25% of full sunlight. RGR, Asat, leaf and root respiration (Rd), and N uptake rate per unit root mass or length differed significantly among species, ranking (from high to low): Populus, Betula and Larix spp. (all deciduous) and then to five evergreen conifers (Pinus, Picea and Thuja spp.), which were generally comparable in these measures. 3.Asat, leaf and root Rd and N uptake rates were all correlated (r≈ 0·8 to 0·9) with species traits, such as seed mass, leaf life span and shade-tolerance rankings. Mass-based Asat was greater in conifer seedlings raised in low than high light. In contrast, area-based Asat was higher for plants grown in high than low light, especially in the deciduous species. Once adjusted for differences in plant mass, leaf or root respiration rates did not differ for plants grown in low vs high light. 4. Interspecific variation in RGR was positively correlated (r≈ 0·9) with rates of photosynthesis, respiration and N uptake. Leaf photosynthesis and respiration rates were correlated to specific leaf area and leaf N concentrations (r≈ 0·9). Root respiration rates, N uptake rates, specific root length (root length per root dry mass) and root N concentrations were all highly correlated with each other (r≈ 0·8 to 0·9). These data suggest a close coupling of tissue-level metabolism, chemistry and structure with whole-plant performance and species ecophysiological and life-history traits.

Summary 1. To test hypotheses concerning adaptation and acclimation of tree species to shaded habitats we determined the growth, biomass partitioning and morphology of seedlings of nine near-boreal tree species in high- and low-light greenhouse environment (25 and 5% of full sunlight, respectively), comparable to sunlit gap and shaded microsites in boreal forests. The species differ widely in shade tolerance, seed size and leaf life span. 2. In low light, all species allocated proportionally more biomass to stems and less to roots, but the same to foliage, compared with the high-light environment. At a common size, all species had finer leaf morphology (higher specific leaf area, SLA) but coarser root morphology (lower specific root length, SRL) in low than high light. From a whole plant perspective, all species enhanced leaf area per unit plant mass (leaf area ratio, LAR) in low light and root length per unit plant mass (root length ratio, RLR) in high light. 3. Shade-intolerant deciduous species had higher RGR, SLA and SRL than larger seeded evergreens: ranking from Populus, Betula and Larix spp., then to five evergreen Pinus, Picea and Thuja spp., which were generally comparable in these traits. There were no changes in growth rankings of species between high- and low-light environments, nor consistent differences among species in biomass partitioning. Hence, species differences in leaf and root morphology (SLA, SRL) drove whole plant patterns, such as Populus, Betula and Larix had greater total leaf area and root length per unit plant mass (LAR and RLR, respectively) than the evergreens. Interspecific variation in RGR in both high and low light was positively correlated ( r  0·9) with SLA, SRL, LAR and RLR, and negatively correlated (r ‐0·9) to seed mass and leaf life span. 4. These data suggest that SLA, SRL, NAR and RGR are closely associated with variation in life-history traits and that variation in leaf and root structure more strongly influences patterns of RGR among species and light environments than does biomass partitioning.

Models of tree function and forest ecosystem carbon budgets often assume that potential global changes in temperature and/or other factors may alter tissue nitrogen (N) and dark respiration rates (R d ). However, little is known of patterns of co-variation in tissue N and R d among intraspecific populations originating along climatic gradients, and of whether an N-based model of R d can link these two variables. To address these issues, we studied N and R d in fully expanded needles of 10-year-old trees of 14 Scots Pine (Pinus sylvestris) populations of wide-ranging origin (43 ° to 60 °N), grown under common garden conditions. For 11 lowland populations (elevation < 200 m) from the contiguous part of the species range (48 ° to 60°N) grown at a field site in Kornik, western Poland (52 °N), there were greater needle %N in populations from increasing latitude of origin or decreasing mean annual temperature (r≥0.93, P