Needle Longevity Research Articles

SYSTEMATIZATION OF CALCULATIONS FOR THE RELIABILITY OF ELEMENTS OF KNITTING MECHANISMS OF SOCKS MACHINES

The paper covers a wide range of issues in terms of longevity and reliability, which are presented in the modern theory and practice of designing for elements of knitting systems of sock machines. The relevance of the work is confirmed by the current trend in the production and modernization of relatively small batches of machines, which requires a reduction in time and cost of design, primarily due to the calculation recommendations. The analysis and generalizations concerning the choice of calculations on longevity in deterministic and reliability in probabilistic statements for details of difficult forms and limited in the sizes are offered, in particular knitting needles and malleable working surface of cams, which are characterized by random loads and variations of strength characteristics of materials. The mathematical apparatus for the analysis of influence on fatigue longevity of needles of increase of speed parameters of the automatic machine and of constructive measures for reduction of loadings in pair of a needle and cams is presented.. A complex approach is presented for knitting needles for the security of the given fatigue longevity using of the position of the dynamic analysis, calculation of the loading, mathematical statistics and the theory of probability, which allows to quickly evaluate the effectiveness of the proposals to constructive and technological solutions. The dependences for the calculations of cams of different construction for fatigue strength in the probabilistic setting, which in comparison with traditional (according to the normalized factor of safely) a sufficient level of reliability while minimizing of size. Specifics for cams with malleable working surface of equal reliability and with the provision of simultaneous beam and double cantilever deformations are presented. Shown the expediency of using trapezoidal consoles of equal resistance and the algorithm for calculating the sizes of their root and end sections according to the coefficient of shape and a given deflection, which minimizes the length of the cam consoles. The advantages of computer modeling by the finite element method are listed, primarily obtaining the final results with sufficient accuracy and convenience for analysis.

TO CALCULATE THE LOADING OF KNITTING NEEDLES OF AUTOMATIC HALF-HOSE MACHINES

An important link in the analysis of the longevity of details by the criterion of fatigue strength is the calculation of parameters that take into account the peculiarities of the technological regime in terms of load and the corresponding number of cycles that affect the accumulation of fatigue failure. The final range of loads of knitting needles of automatic half-hose machine was based on the systematization of amplitudes of forces depending on the frequency of their implementation. Previous works has assumed the assumption of a one interaction of the needle heel with the cams, which is experimentally refuted by the example of modern high-speed automatic half-hose machine. The aim of the work is to adjust the provisions of calculating the load of knitting needles of half-hose machines for design estimate of longevity, taking into account the specific features of the impacts of needles with the cams of the knitting system, which affect the total number of load cycles. The condition of rupture of the contact in the pair of the needle heel and the inclined cam after their impact is considered, taking into account the inertial and rigid parameters of the system, including the resisting force of the needle in the groove of the cylinder. According to the results of the dynamic analysis, the expressions of the minimum speed at which the needle can rebound from the cam and the vertical component of the needle rebound speed at the moment of its separation from the cam are obtained. The analysis of the influence of the force of resistance of the needle movement in the race on the vertical speed of the needle is performed. The issue of the bounce of the heels of unselected needles from the lower edge of the inclined cam due to their inertial run-out was studied separately. It is established that at certain circular speeds of the needle cylinder leads to additional impacts of the needles with the horizontal limiting cams and increases their destruction. The results of studies of the possible rebound of the needle heel from the inclined cam and the interaction of the needle with the limiting horizontal cams are a supplement to the method of calculating the loading of needles and are aimed at improving the accuracy of design longevity of needles.

Estimation of Fatigue Longevity of Rod Elements of Complex Form

The questions of design maintenance of a given fatigue longevity of rods of complex form during the intensification of load modes without changing of geometric, inertial and rigidity parameters of roads are considered. The study is conducted on the example of needles of circular machines with a small diameter of cylinder (automatic half-hose machines). An approach, based on the system of calculation of loads, loadings and resources under the criterion of fatigue strength, is proposed. The key link for the transition from the results of dynamic analysis to the determination of reliability indices is the dependence of limited longevity of needles on the cycles of load to fatigue failure with the use of statistical data on operating time to fatigue failure of the needles in production conditions. Since the random values of loads of the needles do not obey the normal law of distribution, the general description of density of distribution of amplitude of loads is presented. The influence of increase in speed parameters and constructive measures, aimed to reduce the corresponding loads at a current size of critical section of the needles, on the fatigue longevity is analyzed.

Variations in leaf economics spectrum traits for an evergreen coniferous species: Tree size dominates over environment factors

Abstract Many leaf traits strongly vary with tree size and environmental factors, but the importance of these factors to intraspecific variations of leaf traits in forest trees has rarely been simultaneously evaluated. We measured needle longevity and specific leaf area (SLA) and nitrogen (N) content of every needle age (0‐ to 4‐year old) for 65 individuals with 0.3–100 cm diameter at breast height (DBH) for an evergreen coniferous species, Pinus koraiensis Sieb. et Zucc., in Northeast China. We simultaneously evaluated the effects of tree size (DBH or tree height) and environment factors (light intensity, soil N content and water availability) on the needle longevity, SLA, foliage N content as well as the slopes of regressions of SLA and foliage N content against needle age. All of the studied leaf traits and slopes of regressions of SLA and foliage N content against needle age were significantly related to tree size. Tree height had a greater impact on SLA and area‐based leaf N content (Narea), whereas DBH was more important for needle longevity and mass‐based leaf N content (Nmass). The environment variables, light intensity, soil N content and water availability, were rather minor factors for trait variations compared with tree size. Significant influence of light intensity was found only on needle longevity, and soil N and water availability had no effects on the leaf traits. Our study clearly showed that tree size is an important driver of intraspecific variations in the key leaf traits of P. koraiensis in a natural forest. We also emphasize the importance of DBH or tree height varies depending on leaf traits, suggesting various mechanisms of size effects on the intraspecific variations in leaf traits. We suggest that ecological significance of leaf trait variations needs reconsideration incorporating tree size effect. A free Plain Language Summary can be found within the Supporting Information of this article.

Cold adaptation drives variability in needle structure and anatomy in Pinus sylvestris L. along a 1,900 km temperate–boreal transect

Abstract Occupancy of cold habitats by evergreen species requires structural modification of photosynthetic organs for stress resistance and longevity. Such modifications have been described at interspecific level, while intraspecific variation has been underexplored. To identify structural and anatomical traits that may be adaptive in cold environments, we studied intraspecific variability of needles of Scots pine (Pinus sylvestris L.), a wide‐ranging tree, along a 1,900 km temperate–boreal transect in Europe. Needles from 20 sites representing mean minimum winter temperatures between −4.0 and −19.9°C and mean annual temperatures between 8.3 and −1.7°C were sampled for measurements of leaf mass per area (LMA, g/m2), leaf density (LD, g/cm3) and 30 other morpho‐anatomical traits. Needles from cold sites lived longer, were shorter, showed higher LMA and LD, had narrower and more collapse‐resistant tracheids, thicker epidermal cells with thicker cell walls and wider resin ducts occupying larger fraction of needle volume in comparison to needles from warmer sites. Along the steep climatic gradient, needles presented a coordinated phenotypic spectrum of external and internal traits that are largely interpretable in functional, adaptive terms. This intraspecific pattern of covarying traits provides insight into the adaptive syndrome associated with stress tolerance and extended needle longevity under cold conditions of high latitudes. A plain language summary is available for this article.

Needle longevity of balsam fir is increased by defoliation by spruce budworm

Retention of 10–16-year-old balsam fir needles increased significantly with cumulative spruce budworm defoliation. Mean needle longevity on defoliated 50-year-old fir was almost double that for undefoliated 25-year-old fir. Conifers experiencing environmental change affecting photosynthetic capacity have been observed to compensate by adjusting foliage longevity and increasing retention of old foliage. Defoliation by spruce budworm [Choristoneura fumiferana (Clem.)] is one such change, therefore, it was hypothesized that conifers, such as balsam fir [Abies balsamea (L.) Mill.] may increase foliage life spans to compensate for losses of photosynthetic capacity to defoliation. Understanding foliage longevity is a key component of predicting foliage complement, which is the main driver of effects of defoliation on forest growth and productivity. Defoliation and needle loss were assessed on 16 age classes of foliage on mid-crown branches sampled from 134 mature balsam fir trees near Amqui and Causapscal, Quebec, and related to needle age and cumulative defoliation (summed annual defoliation from 2012 to 2016). A general linear mixed model fitted to the needle survivorship data accounted for 68% of the total deviance. The model interaction term of cumulative defoliation with foliage age indicated that for foliage ages less than about 9 years, increased cumulative defoliation resulted in lower needle survival, possibly because of backfeeding of spruce budworm on 5+-year-old foliage, while in the older age classes, needle survival increased with increasing cumulative defoliation. For the oldest, 11–16-year-old foliage age classes, 10–16% more foliage per age class was retained under severe defoliation than under light defoliation. As a result, median needle age increased from 9.5 to 10.4 years as cumulative defoliation increased from 0 to 500%. Mean needle longevity of 9.5 years for 50-year-old balsam fir with low defoliation observed in this study was considerably higher than the mean of 5.5 years previously observed for 22- to 27-year-old fir in Cape Breton, Nova Scotia. Such differences in needle longevity and retention would cause considerable differences in predictions of tree growth using foliage-based stand growth models.

Variability in needle lifespan and foliar biomass along a gradient of soil fertility in maritime pine plantations on acid soils rich in organic matter

The variability in needle lifespan, foliar biomass and leaf area index was studied in 31 Pinus pinaster Ait. plots in Galicia (NW Spain), established along a gradient of soil productivity in plantations of similar age (11–14years). The soils under study were acidic (pH 3.7–5.3) and very rich in organic matter (6.9–34.3%). All needles were classified according to age class, and presence/absence of needles was recorded to evaluate survival. Specific leaf area and needle biomass were calculated for each plot. The foliage nutrient concentrations were also measured and site index was calculated. The maximum needle age was 5years. Survival of needles older than 2years declined rapidly. Needle longevity was positively affected by site index and foliar nutrient concentrations, particularly of Mg and K. This suggests that maritime pine responds to low soil fertility by decreasing needle lifespan at local scales. Needle biomass and leaf area index were significantly higher in 1 and 2-year-old needles. Total needle biomass and LAI values were very variable (average values of 4.89tha−1 and 1.64m2m−2, standard deviation 3.1 and 1.1 and CV of 64% and 69%, respectively) and were positively related to site productivity and foliar nutrients. The average litterfall rate was estimated to be 0.31year−1. The mean growth efficiency (0.36kgm−2year−1) was also rather variable (CV=50%) and was positively related to foliar K and needle longevity. The relationships between all variables associated with high levels of pine productivity and the mean shrub height were always significant and negative, indicating a reduction in the risk of ground fire.

Correction for Reich et al., Biogeographic variation in evergreen conifer needle longevity and impacts on boreal forest carbon cycle projections

Correction for Reich et al., Biogeographic variation in evergreen conifer needle longevity and impacts on boreal forest carbon cycle projections

Biogeographic variation in evergreen conifer needle longevity and impacts on boreal forest carbon cycle projections.

Leaf life span is an important plant trait associated with interspecific variation in leaf, organismal, and ecosystem processes. We hypothesized that intraspecific variation in gymnosperm needle traits with latitude reflects both selection and acclimation for traits adaptive to the associated temperature and moisture gradient. This hypothesis was supported, because across 127 sites along a 2,160-km gradient in North America individuals of Picea glauca, Picea mariana, Pinus banksiana, and Abies balsamea had longer needle life span and lower tissue nitrogen concentration with decreasing mean annual temperature. Similar patterns were noted for Pinus sylvestris across a north-south gradient in Europe. These differences highlight needle longevity as an adaptive feature important to ecological success of boreal conifers across broad climatic ranges. Additionally, differences in leaf life span directly affect annual foliage turnover rate, which along with needle physiology partially regulates carbon cycling through effects on gross primary production and net canopy carbon export. However, most, if not all, global land surface models parameterize needle longevity of boreal evergreen forests as if it were a constant. We incorporated temperature-dependent needle longevity and %nitrogen, and biomass allocation, into a land surface model, Community Atmosphere Biosphere Land Exchange, to assess their impacts on carbon cycling processes. Incorporating realistic parameterization of these variables improved predictions of canopy leaf area index and gross primary production compared with observations from flux sites. Finally, increasingly low foliage turnover and biomass fraction toward the cold far north indicate that a surprisingly small fraction of new biomass is allocated to foliage under such conditions.

Climatic influences on needle cohort survival mediated by Swiss needle cast in coastal Douglas-fir

Swiss needle cast (SNC) severity in Douglas-fir (Pseudotsuga menziesii) has been shown to vary spatially and temporally in response to climatic factors both within its native range and in regions where it has been planted as an exotic species. Survival models were developed for different Douglas-fir needle cohorts to enhance our understanding of how climatic influences on needle longevity are mediated by SNC in the Oregon Coast Range. The climate-based models were based on repeated measurement of 100 plots between 1998 and 2005 coupled with downscaled PRISM climate data. Potential predictors of needle survival by annual cohort were selected from numerous climatic variables at annual, seasonal, and monthly scales. Needle survival probability was positively associated with maximum summer temperature, and negatively associated with minimum winter temperature and spring precipitation. Seasonal climate variables associated with needle longevity are consistent with current epidemiological understanding of Phaeocyrptopus gaeumannii, as well as with previous analyses of climatic influences on SNC severity as measured by average years of foliage retention and frequency of fungal fruiting bodies, or pseudothecia, in stomates.

Latitudinal variation in morphological traits of the genus Pinus and its relation to environmental and phylogenetic signals

Background: Broad-scale analysis of interspecific trait variation is a fundamental approach in comparative ecology to investigate general species–environment relationships, but inferences from environmental and phylogenetic signals are still controversially discussed. Aims: The aim of this study was to globally analyse the genus Pinus and the interspecific variation of morphological traits with latitude as a surrogate of broad-scale environmental changes, and to compare latitudinal trait correlations with biogeographic, environmental and phylogenetic signals in trait variation. Methods: Based on native range maps of 103 Pinus species, the latitudinal correlations of nine morphological traits, including needle characters, cone length and tree height were calculated. Principal component analysis was used to explore trait covariation. Variation partitioning was applied to disentangle environmental and phylogenetic signals in trait variation. Results: Strong latitudinal correlations were detected for traits, such as needle length:width ratio or needle longevity, with similar trends for different taxonomic species subsets and geographic regions. Strong latitudinal correlations were related to a decrease in the pure phylogenetic signal and to an increase in the phylogenetically structured environmental variation (PSEV), whereas the pure environmental signal was almost negligible. Conclusions: Besides a ranking of traits that differ in environmental and phylogenetic signals, our results showed a general relationship between increasing latitudinal trait correlation and an increase in PSEV, which indicates phylogenetic niche conservatism. Thus, for the investigated morphological traits of the genus Pinus both environmental and phylogenetic signals are directly linked by PSEV to broad-scale spatial patterns in trait variation.

Needle longevity as a criterion of response to a climatic fluctuation (so called heat wave) in Scots pine populations at early phases of ontogeny

The paper presents results of an assessment of needle age classes in Scots pine partial populations in the period of three and five years after outplanting in a lowland site in relation to conditions created by climatic elements. The method is based on Skuhravý’s (1987) description when the state of needle age classes of the third whorl (from the apex) is evaluated just once. Five-year summary of meteorological data was assessed according to the criteria of determination of periods of heat waves and dry spells. Differences in numbers of living needle age classes in the groups of Scots pine populations in the period of three and five years after their outplanting in permanent lowland sites proved the highest total number of living needle classes in the group of local lowland populations. On the contrary, the lowest total number of living needle classes was found out in the group of mountain populations. Critical climatic periods are overlaps of heat waves and dry spells that illustrate the complexity of moisture and temperature conditions of lowland sites. Although the Scots pine is a xerophytic species, it responded to the cumulation of adverse factors by accelerated needle senescence. Its physiological response to heat and dry stress consists in needle shedding, i.e. reduction in the assimilating area. As mountain populations are not usually exposed to heat waves, the impact of this phenomenon on them was the highest. On the other hand, the local (lowland) populations carrying information on the patterns of local climate from the reproduction period do not undergo any marked reduction in needle age classes.  

Photosynthetic rate, needle longevity, and nutrient contents in Picea glehnii growing on strongly acidic volcanic ash soil in northern Japan

Picea glehnii Masters can grow in strongly acidic volcanic ash soil (pH 3.6) in northern Japan. We compared needle longevity, photosynthetic rate, and concentrations of elements in needles, in mature trees of P. glehnii growing in volcanic ash soil and in brown forest soil (pH 5.4). P. glehnii growing in volcanic ash soil showed suppressed photosynthetic rate and growth by the deficiency in nitrogen compared with its growth in brown forest soil. However, the younger needles of P. glehnii growing in volcanic ash soil maintained a high photosynthetic rate, as a result of large amounts of remobilized nitrogen from senesced needles. Needles of P. glehnii growing in volcanic ash soil did not show deficiencies in Ca, Mg, or K. Moreover, Al was at low levels in the needles, suggesting that P. glehnii was able to avoid Al toxicity by Al exclusion. P. glehnii thus exhibits great ability to adapt to an acidic environment.

Convergence of leaf display and photosynthetic characteristics of understory Abies amabilis and Tsuga heterophylla in an old-growth forest in southwestern Washington State, USA

We compared the morphological and physiological characteristics of understory trees of Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes and Tsuga heterophylla (Raf.) Sarg. growing adjacent to each other in an old-growth forest in southwestern Washington State, USA. We hypothesized that, despite contrasting branching patterns and crown architectures, the two species should exhibit convergence in leaf display and photosynthetic gain per light intercepting area, because these are important properties determining their survival in the light-limited understory. The branching pattern of A. amabilis was regular (normal shoot-length distribution, less variable branching angle and bifurcation ratio), whereas that of T. heterophylla was more plastic (positively skewed shoot-length distribution, more variable branching angle and bifurcation ratio). The two species had similar shoot morphologies: number of leaves per unit shoot length and leaf to axis dry mass ratio. Leaf morphology, in contrast, was significantly different. Leaves of A. amabilis were larger and heavier than those of T. heterophylla, which resulted in lower mass-based photosynthetic rate for A. amabilis. Despite these differences, the two species had similar levels of leaf overlap and area-based photosynthetic characteristics. Needle longevity of A. amabilis was nearly twice that of T. heterophylla. The leaf N contents of current and 1-year-old leaves were lower for A. amabilis than for T. heterophylla. However, the leaf N content of A. amabilis did not change from current leaves to 6-year-old leaves, whereas that of T. heterophylla decreased with increasing leaf age. Abies amabilis had deeper crowns than T. heterophylla and retained branches with low relative growth rates. Longer branch retention may compensate for the lower branch-level assimilation rate of A. amabilis. We inferred that the convergence of leaf display and photosynthetic characteristics between A. amabilis and T. heterophylla may contribute to the persistence of both species in the understory of this forest.

Physiological acclimation of Pinus flexilis to drought stress on contrasting slope aspects in Waterton Lakes National Park, Alberta, Canada

Photosynthetic gas-exchange characteristics were measured in Pinus flexilis James (limber pine) during two drought years in a xeric, subalpine ecosystem of the Rocky Mountains. Limber pine exhibited conservative water-use traits, including low specific leaf area, leaf nitrogen, stomatal conductance, transpiration (E), and light-saturated net photosynthesis (Amax), but exhibited high needle longevity, water-use efficiency (Amax/E), and stable carbon isotope composition. Net photosynthesis declined strongly with leaf-to-air vapour pressure deficit, resulting in a bimodal seasonal pattern of Amax. Although very little gas exchange was observed in late summer, photosynthetic activity extended into October. The avoidance of gas exchange during high atmospheric demand maximized whole-season water-use efficiency. Leaf temperature and leaf-to-air vapour pressure deficit were higher on south-facing slopes during both moderate (2006) and severe (2007) drought. Severe drought caused lower stomatal conductance and E on the southeast-facing slope, but neither Amax nor canopy reflectance indices differed among slope aspects. Although Amax was lower in 2007 than 2006, branch-length increment did not differ. Foliar stable carbon isotope composition was higher in needles produced in dry years but did not vary among slope aspects. These results indicate that physiological acclimation to water stress prevented among-aspect differences in Amax and that shoulder-season photosynthesis may become increasingly important in a warmer climate.

Growth characteristics of Sakhalin spruce (Picea glehnii) planted on the northern Japanese hillsides exposed to strong winds

Sakhalin spruce (Picea glehnii), a native species typically found in northern Japan, has been used in reforestation on hillsides exposed to strong winds. In the reforestation areas, there are south-facing (S-slope) and northwest-facing slopes (NW-slope). Climatic conditions are contrasting between the two slopes, with shallower snow cover on the S-slopes. We compared growth responses of the spruce to micro-environment between the S- and NW-slopes through soil nutrients, needle longevity, water status, photosynthesis, and nutrients in the needles. These parameters were measured in needles exposed above the snow in winter and in lower needles protected by snow cover. High-position needles suffered from drought stress, especially in winter, and needles were shed early in the year on both slopes. Low-position needles did not suffer from drought stress, and maintained a high photosynthetic rate on both slopes. However, needle longevity was reduced on the S-slope, and concentrations of nitrogen, phosphorus, and potassium in the needles decreased with needle age. Soil nutrient concentrations were low on the S-slope, which suggests that the needles on the S-slope may remobilize nutrients from aged needles to younger needles prior to shedding. This characteristic is probably an adaptation in Sakhalin spruce to poor soil conditions.

Needle longevity, photosynthetic rate and nitrogen concentration of eight spruce taxa planted in northern Japan

Growth characteristics of Picea glehnii Masters, P. jezoensis (Sieb. et Zucc) Carr., P. jezoensis var. hondoensis (Mayr) Rehder and P. shirasawae Hayashi from Japan, P. abies (L.) Karst. from Europe and P. glauca Voss, P. mariana Britt., Sterns and Pogg. and P. rubens Sarg. from North America were compared. The trees were grown in similar conditions at the Tomakomai Experimental Forest of Hokkaido University in northern Japan. Tree growth, needle biomass, longevity, photosynthetic rate, nitrogen concentration and specific leaf area (SLA) were measured, and photosynthetic nitrogen-use efficiency was calculated. Picea jezoensis, P. jezoensis var. hondoensis, P. abies and P. glauca had high growth rates, high photosynthetic rates in young needles, high needle nitrogen concentrations and short needle life spans. In contrast, P. glehnii, P. shirasawae, P. mariana and P. rubens had low growth and photosynthetic rates, low needle nitrogen concentrations, long needle life spans and maintained a high photosynthetic nitrogen-use efficiency in older needles. Examination of relationships between several growth parameters of the eight taxa revealed positive correlations between SLA and mass-based photosynthetic rate and between SLA and mass-based nitrogen concentration, whereas mass-based photosynthetic rate and mass-based nitrogen concentration were negatively correlated with needle longevity. The species differed greatly in growth characteristics despite being grown in similar conditions.

Variation in Scots pine needle longevity and nutrient conservation in different habitats and latitudes

Within-species variation in needle traits is an important characteristic of conifers enabling trees to grow in different environments. We compared mean needle age (NA), shoot growth, and nutrient conservation in Scots pine ( Pinus sylvestris L.) populations in different habitats and latitudes (peatlands and Vaccinium -type stands in Estonia (59°N) and Lapland (66°30′N)). In Vaccinium-type stands, trees with higher NA (mostly in Lapland) had lower shoot length increment and lower concentration of nitrogen and phosphorus in current-year needles than trees with low NA (mostly in Estonia). However, in peatlands, variation in NA (which was as high as in the Vaccinium-type stands) was weakly or insignificantly related to shoot growth and needle nutrient concentration. Within latitudes, pines with different shoot length increments and needle nutrient concentrations tend to have similar NAs. Resorption efficiency and concentration of nitrogen and phosphorus in senescent needles decreased with the initial concentrations of these nutrients in green needles. Our results demonstrate that slow growth and low needle nutrient concentration are not necessarily followed by higher NA and greater nutrient conservation in Scots pine. This is the opposite of the results often obtained in among-species comparisons or within species along latitudinal and altitudinal gradients.

Biomass distribution of different-aged needles in young and old Pinus cembra trees at highland and lowland sites

Conifer needles of different ages perform differently in ecophysiology. However, no study has investigated the biomass distribution of different-aged needles in a tree crown or/and a stand canopy. We carried out a study on young (∼50 years old) and old (∼200 years) Pinus cembra L. trees at highland (2100–2300 m a.s.l.) and lowland (570 m) sites in Switzerland. We found that both the young and the old trees living in the highlands had more needle biomass per tree than the same-aged trees of the same species living in the lowlands. This is mainly due to the greater longevity of needles in highland trees. It reflects the strategic responses of trees to low resource availability or high abiotic stress level. Having older needles increases the time that nutrients are resident in trees in less favorable environments, and compensates for shorter growing period in cold temperatures.

안산 공단지역에 식재된 소나무류 2종의 생장과 생리학적 반응

안산 공단지대에 식재되어 있는 잣나무와 리기다소나무의 생장 저하의 실태와 그 원인을 구명하기 위하여 생장 및 생리학적 반응을 중심으로 대조구와 비교 고찰하였다. 피해구에 식재 되어 있는 두 수종의 침엽 내 Mn, F 그리고 Cl의 농도는 대조구에 비하여 유의적으로 높았으며, 2년생 3년생으로 갈수록 급격히 그 농도가 증가하였다. 또한 필수 영양 원소인 P와 클로로필 함량은 피해구가 대조구에 비하여 유의적으로 감소하였으며, 또한 침엽의 연령이 증가함에 따라 급격히 감소하였음을 알 수 있었다. 한편, 피해구에 식재되어 있는 두 수종의 최대 광합성률, 양자수율<TEX>$(\Phi)$</TEX>, 카르복실레이션효율(CE)등의 광합성 능은 대조구에 비하여 현저히 감소하였다. 이상과 같이 독성 원소의 축적 및 필수 영양 원소의 부족 등 환경 스트레스에 의한 수목 생리활동의 저하가 수목 생장 저하의 직접적인 원인으로 판단된다. We investigated the effects of pollutants on two pine species (Pinus koraiensis and Pinus rigida) in an industrial region, using a physiological approach. We measured the growth and physiological parameters (photosynthetic activity and chemical contents) of the pine trees in relation to environmental pollutants. The concentrations of manganese (Mn), fluorine (F) and chlorine (CI) in needles of two pine species at the damaged site were significantly higher than those at the control site, and concentrations of essential elements (P) and chlorophyll in needles at the damaged site were significantly lower than at the control site. The light-saturated net photosynthesis <TEX>$(P_{sat})$</TEX>, apparent quantum yield <TEX>$(\Phi)$</TEX>, carboxylation efficiency (CE) of both pines at the damaged site were significantly lower than those at the control site. The length of shoots and survivorship of needles of two pines at the damaged site were significantly lower than those at the control site. Especially, at damaged site, growth of shoots and needle longevity of P. koraiensis are larger than those of P. rigida.