Growth and carbon accumulation in root systems of Pinus taeda and Pinus ponderosa seedlings as affected by varying CO(2), temperature and nitrogen

It has been hypothesized that increasing atmospheric CO(2) concentration enhances accumulation of carbon in fine roots, thereby altering soil carbon dynamics and nutrient cycling. To evaluate possible changes to belowground pools of carbon and nitrogen in response to elevated CO(2), an early and a late successional species of pine (Pinus taeda L. and Pinus ponderosa Dougl. ex Laws, respectively) were grown from seed for 160 days in a 35 or 70 Pa CO(2) partial pressure at low or high temperature (30-year weekly mean and 30-year weekly mean + 5 degrees C) and a soil solution nitrogen concentration of 1 or 5 mM NH(4)NO(3) at the Duke University Phytotron. Seedlings were harvested at monthly intervals and growth parameters of the primary root, secondary root and tap root fractions evaluated. Total root biomass of P. ponderosa showed a positive CO(2) response (105% increase) (P = 0.0001) as a result of significant increases in all root fractions in the elevated CO(2) treatment, but all other main effects and interactions were insignificant. In P. taeda, there were significant interactions between CO(2) and temperature (P = 0.04) and CO(2) and nitrogen (P = 0.04) for total root biomass. An allometric analysis indicated that modulation of the secondary root fraction was the main response of the trees to altered environmental conditions. In P. ponderosa, there was an increase in the secondary root fraction relative to the primary and tap root fractions under conditions of low temperature. In P. taeda, there was a shift in carbon accumulation to the secondary roots relative to the primary roots under low temperature and low nitrogen. Neither species exhibited shifts in carbon accumulation in response to elevated CO(2). We conclude that both species have the potential to increase belowground biomass substantially in response to rising atmospheric CO(2) concentration, and this response is sensitive to temperature and nitrogen in P. taeda. Both species displayed small shifts in belowground carbon accumulation in response to altered temperature and nitrogen that may have substantial ecosystem consequences over time.     

Atmospheric carbon dioxide, irrigation, and fertilization effects on phenolic and nitrogen concentrations in loblolly pine (Pinus taeda) needles

Concentrations of total soluble phenolics, catechin, proanthocyanidins (PA), lignin and nitrogen (N) were measured in loblolly pine (Pinus taeda L.) needles exposed to either ambient CO(2) concentration ([CO(2)]), ambient plus 175 or ambient plus 350 micromol CO(2) mol(-1) in branch chambers for 2 years. The CO(2) treatments were superimposed on a 2 x 2 factorial combination of irrigation and fertilization treatments. In addition, we compared the effects of branch chambers and open-top chambers on needle chemistry. Proanthocyanidin and N concentrations were measured in needles from branch chambers and from trees in open-top chambers exposed concurrently for two years to either ambient [CO(2)] or ambient plus 200 micromol CO(2) mol(-1) in combination with a fertilization treatment. In the branch chambers, concentrations of total soluble phenolics in needles generally increased with needle age. Concentrations of total soluble phenolics, catechin and PA in needle extracts increased about 11% in response to the elevated [CO(2)] treatments. There were no significant treatment effects on foliar lignin concentrations. Nitrogen concentrations were about 10% lower in needles from the elevated [CO(2)] treatments than in needles from the ambient [CO(2)] treatments. Soluble phenolic and PA concentrations were higher in the control and irrigated soil treatments in about half of the comparisons; otherwise, differences were not statistically significant. Needle N concentrations increased 23% in response to fertilization. Treatment effects on PA and N concentrations were similar between branch and open-top chambers, although in this part of the study N concentrations were not significantly affected by the CO(2) treatments in either the branch or open-top chambers. We conclude that elevated [CO(2)] and low N availability affected foliar chemical composition, which could in turn affect plant-pathogen interactions, decomposition rates and mineral nutrient cycling.     

Growth and wood density of Pinus taeda L. as affected by shelterwood harvest in a two-aged stand in Southern Brazil

Pine plantations are an important wood source in Brazil, with Pinus taeda being most frequently planted. Most pinewood is directed to the paper and pulp industry, but there is an increasing demand for wood for solid end-uses, requiring large stems from longer rotations which can be obtained using P. taeda as the canopy in two-aged stands. We evaluated radial growth and wood density at different stem heights of P. taeda in the highlands of Southern Brazil over a production period of 36 years and subjected to shelterwood harvest. Cross-sectional disks were obtained from 15 trees in different stem heights; 10 were used for growth analyses and 5 for growth and density analyses. We used disk images and X-ray techniques for growth and density analyses, respectively. Samples were analyzed for ring (width and density), earlywood, and latewood (width, density, and proportion). Ring width varied between 0.4 and 1.7 cm, with the widest rings in the first years (3–5 years.) of growth. Ring density increased with age, with higher densities on the lower stem portions. Mature wood started to be formed from the 16th ring onwards. Shelterwood harvest affected both ring width and density, but the effects on ring width lasted for at least 5 years, while the effects on wood density were short-lasting. Mature P. taeda trees increased their size after the shelterwood harvest without compromising their wood density. Longer production periods of P. taeda as retained trees in the canopy of two-aged stands provide high-quality wood for structural purposes.

     

Loblolly pine (Pinus taeda L.) essential oil yields affected by environmental and physiological changes

ABSTRACT

Loblolly pine (Pinus taeda L.) is one of the most abundant timber species in the United States and needles from this species contain essential oils (EOs) with antibacterial properties. Needles from trees of one loblolly pine clone were assayed for the EOs α-pinene, β-pinene, terpineol, limonene, and caryophyllene across a growing season. Results showed strong positive correlations among EOs, except for caryophyllene, with Pearson’s correlation values ranging from .66–.96. Simultaneously, physiological attributes of tree stomatal conductance, water stress, and environmental attributes including soil moisture, photosynthetic active radiation (PAR), temperature, wind speed, and relative humidity were measured. The plants modulated the EO concentrations as a function of a changing environment season. The collection month had the largest effect on EO yields and highest yields were during the beginning of the growing season. Decreases in EOs were evident as the growing season progressed and as plants exhibited greater water stress, temperatures, solar radiation, and less stomatal conductance and soil moisture. Loblolly pine’s main constituents of EOs were tightly linked and were influenced by seasonal changes (i.e., month); still, environmental/physiological attributes exhibited significant effects on α-pinene, β-pinene, and limonene concentrations. Early spring conditions with ample water were most conducive to high concentrations of EOs.     

Distribution of (14)C-labeled photosynthate in loblolly pine (Pinus taeda) seedlings as affected by season and time after exposure

Distribution of (14)C-labeled photosynthate was determined in field-grown loblolly pine (Pinus taeda L.) seedlings on August 9 and October 15, 1984 and January 15 and March 12, 1985. Leaves on a lateral branch fixed (14)C photosynthetically and amounts of (14)C in seven biochemical fractions in each of six plant parts were determined 8, 24, and 72 h later. In all treatments, (14)C uptake was approximately 96% of that originally presented. Respiratory loss of (14)C ranged from 22 to 87% of uptake and increased sharply with increasing time after exposure and as the seedlings grew larger later in the study. Most (14)C was found in exposed leaves and very little occurred above the exposed branch. Amounts of (14)C decreased in the exposed leaves and increased in the roots with time after exposure and date. Sugars were generally the most heavily labeled fraction. Labeled sugar content of exposed leaves decreased by more than half between 8 and 72 h as sugars were metabolized and translocated to other parts, primarily the roots. In roots, the labeling of starch and residue (structural compounds) increased greatly with transport time and season. In all plant parts, proteins and amino acids contained very little (14)C regardless of date or time.     

湿地松、火炬松适应性分析

在同样的立地条件和抚育条件下,在1~20 a内,湿地松的生长明显优于火炬松和马尾松。20~30 a内,国外松生长不如马尾松,而且对地力的适应性也不如马尾松。作为短轮伐期的速生丰产纸浆林,湿地松是适应性比较强的速生丰产的引进树种,但在立地差、集约度低或海拔高处应以本地树种马尾松为主。     

Belowground carbon dynamics in loblolly pine (Pinus taeda) immediately following diammonium phosphate fertilization

Forest soils store an immense quantity of labile carbon (C) and a may be a large potential sink for atmospheric C. Forest management practices such as fertilization may enhance overall C storage in soils, yet changes in physiological processes following nutrient amendments have not been widely investigated. We intensively monitored belowground C dynamics for nearly 200 days following diammonium phosphate fertilization of pot-grown loblolly pine (Pinus taeda L.) seedlings in an effort to examine the short-term effects of fertilization on processes involved in soil C sequestration. Soil respiration rates initially increased in fertilized pots relative to controls, followed by a brief reversal in this trend and then a final sustained pattern of elevated rates of soil respiration in the fertilized treatment. Patterns in soil respiration rates over time reflected changes in autotrophic (root) and heterotrophic (microbial) components of soil respiration. Root respiration rates were greater in the fertilized treatment 49 days following fertilization and returned to control rates by the end of the study. In contrast, microbial respiration rates and microbial activity per soil C concentration remained depressed over the same time period. Compared with control seedlings, total root biomass was 27% greater in fertilized seedlings harvested at the end of the study, indicating that the elevated soil respiration rates observed toward the end of the study were a result of increased respiring root biomass. We conclude that fertilization, at least over the short-term, may increase soil C sequestration by increasing belowground biomass production and reducing microbial driven C turnover.     

Nutrient use and uptake in Pinus taeda

We quantified nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) content, use (nutrient amount for one growth year), retranslocation (nutrients recycled before foliage senescence), uptake (use minus retranslocation), volume production per unit of uptake and fertilizer-uptake efficiency (percent applied taken up) in a 2 x 2 (nutrient and water) factorial experiment replicated four times in an 8-year-old loblolly pine (Pinus taeda L.) stand growing on a nutrient-poor sandy soil in Scotland County, North Carolina, USA. Over 14 years, we applied 1140, 168, 393, 168 and 146 kg ha(-1) of elemental N, P, K, Ca and Mg fertilizer, respectively, and an average of 710 mm year(-1) of irrigation. All plots received complete vegetation control. Fertilization about doubled tissue N, P, K and Mg contents at age 21, whereas irrigation resulted in smaller increases in nutrient contents. Maximum annual uptake was 101, 9.3, 44, 37 and 13 kg ha(-1) year(-1) and volume production per unit of nutrient uptake was 0.35, 3.5, 0.66, 1.1 and 3.1 m(3) kg(-1), for N, P, K, Ca and Mg, respectively. Irrigated plots had greater volume production per unit of N, P, K and Mg uptake than control plots, likely because irrigation allowed photosynthesis to continue during dry periods. Fertilized plus irrigated plots had less volume production per unit of these elements than the fertilized plots either because nutrient uptake exceeded the requirement for optimum growth or because available water (rainfall plus irrigation) was insufficient for the leaf area achieved with fertilization. At age 19, fertilizer-uptake efficiencies for N, P, K, Ca and Mg were 53, 24, 62, 57 and 39%, respectively, and increased with irrigation to 68, 36, 78, 116 and 55%, respectively. The scale of fertilizer uptake was likely a result of low native site nutrient availability, study longevity, measurement of all tissue components on site, a comprehensive assessment of coarse roots, and the 3-m rooting depth. Ecosystem nitrogen retention (applied nitrogen found in living plant material, litter fall and soil to 150-cm depth) was estimated at 79% at age 17, a value that would likely be greater when including soil nitrogen to rooting depth and calculating retention at age 21 when the study ended. The ecosystem retention value provides evidence that intensive site resource management can be accomplished with low likelihood of applied materials moving offsite.     

湿地松、火炬松优良家系选择

对引进美国的湿地松（Pinus elliottii）、火炬松（P．taeda）的生长状况,与当地马尾松（P．massoni-ana）进行比较分析。4年试验结果表明：在广西北部丘陵地,火炬松生长表现良好,树高、胸径、单株材积显著大于马尾松、湿地松;试验所研究10个火炬松家系、1O个湿地松家系生长量,树高、胸径、单株材积生长差异明显;马尾松4年生时,采用种子园种子,轻基质育苗,造林施基肥,生长量与采用母树林种子,黄泥土育苗,不施基肥,树高、胸径、单株材积生长量分别提高了8．6％、19．7％和55．5％。     

Pinus taeda L. response to fertilization,herbaceous plant control,and woody plant control

On an intensively prepared site, a complete fertilizer applied at planting, and control of herbaceous and woody plants for the first 4 years, increased Pinus taeda L. volume at age 5 to 25.9 m³/ha compared to 11.8 m³/ha without the treatments. The fertilizer and competition control factors affected pine growth independently of each other, and so their effects are additive. Herbaceous plant control was the most effective treatment, increasing pine volume by 63%. Declining dry weights of herbaceous plant material indicated that pine was dominant by age 6, so more responses from herbaceous plant control are not expected. Woody plant control did not significantly increase pine volume until the fifth year because the intensive site preparation retarded the development of the woody competition. The fertilizer contained nitrogen, phosphorus, and potassium, but analysis of pine foliage indicates phosphorus was the element causing the response of pine to fertilizer. By the sixth season, the herbaceous and woody plant material contained 31% of the nitrogen and potassium applied as fertilizer. The competing material also contained 7% of the phosphorus applied in the fertilizer. This showed that competitors can be major utilizers of fertilizer applied to pines.     

火炬松不同林龄林地土壤肥力效应研究

通过对福建省漳平五一国有林场内的不同龄级火炬松林分的林地土壤地力性状进行调查研究,结果表明：随着火炬松林分培育年龄的增加,林分自肥能力不断增强,林地的水稳性团聚体和土壤的理化性状均得到较大的改善,并提高了土壤肥力效应,具有较好的改土、保持土壤水分的能力.     

Histopathology of Pinus taeda needles infected by Ploioderma lethale

The histopathology of the host/parasite relationship of Pinus taeda needles infected by the Ascomycete Ploioderma lethale and the morphology of the fructifications of the pathogen were investigated. Amphigenous elliptical teleo‐ and anamorph stromata developed only on dead portions of affected needles. Insertion of the teleo‐ and anamorph stromata in the host needle tissue was subepidermal, and the stromata were covered by a shiny to dull black clypeus. Teleomorph stromata frequently coalesced. Abnormal host tissue was primarily confined to tissues external to the endodermis in the symptomatic portion of affected needles, where a collapse of the mesophyll cells was exhibited. An obvious narrowing of affected needles was observed at the distinct juncture of dead and green tissue. Inter‐ and intracellular hyphae colonized the collapsed mesophyll cell regions, endodermal, transfusion, vascular tissues, and resin ducts. Intercellular hyphae and an interface were present in the living mesophyll cells of the green needle tissue subtending the dead terminal portion of affected needles.     

Pinus contorta growth in northern Sweden as affected by soil scarification

The aim of this study was to quantify the effects of different soil scarification methods on tree growth. Soil scarification influenced stem volume and stem biomass yield of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) in a 17-year-old field trial in boreal Sweden. Soil scarification (disc trenching, mounding and ploughing) resulted in an average stem volume yield of 3.1 and 34.2 m³ ha^–1 on the poor and intermediate sites, respectively, while corresponding values for no soil scarification were 0.9 and 16.7 m³ ha^–1. In comparison to no scarification, ploughing increased volume yields by 500% on the poor site and by 200% on the intermediate sites. The ranking according to stem volume yield was ploughing > disc trenching = mounding no soil scarification. Averaged over the two sites, the mean annual increment of stem biomass was 219% and 145% higher (in d.w., 0.26 kg and 0.34 kg per sample tree) after ploughing compared with no soil scarification, for the average and dominant sample trees, respectively. Although not significant, the increased growth rate after soil scarification decreased the average stem basic wood density of the sample trees with 1.6% and 5.3%, at the poor and intermediate sites, respectively. In conclusion, soil scarification significantly increased the 17-year stem volume yield compared with no scarification. The results also indicate that the difference in stem biomass yield between ploughing and the other methods, especially no soil scarification, will increase even more in the near future.     

Resin flow responses to fertilization, wounding and fungal inoculation in loblolly pine (Pinus taeda) in North Carolina

Resin flow is the primary means of natural defense against southern pine beetle (Dendroctonus frontalis Zimm.), the most important insect pest of Pinus spp. in the southern United States. As a result, factors affecting resin flow are of interest to researchers and forest managers. We examined the influence of fertilization, artificial wounding and fungal inoculation on resin flow in 6- and 12-year-old stands of loblolly pine (Pinus taeda L.) and determined the extent of that influence within and above the wounded stem area and through time. Fertilization increased constitutive resin flow, but only the younger trees sustained increased resin flow after wounding and inoculation treatments. An induced resin flow response occurred between 1 and 30 days after wounding and inoculation treatments. Wounding with inoculation resulted in greater resin flow than wounding alone, but increasing amounts of inoculum did not increase resin flow. Increased resin flow (relative to controls) lasted for at least 90 days after wounding and inoculation. This increase appeared to be limited to the area of treatment, at least in younger trees. The long-lasting effects of fungal inoculation on resin flow, as well as the response to fertilization, suggest that acquired resistance through induced resin flow aids in decreasing susceptibility of loblolly pine to southern pine beetle.     

火炬松引种试验及优良家系选择

对从美国引进的火炬松第1代种子园的25个家系,以湿地松、马尾松为对照在福建省漳平五一国有林场开展引种栽培试验,结果表明:火炬松的生长优于湿地松、马尾松;各家系在树高、胸径和材积等性状上有着显著差异,3个性状的遗传力高,根据性状综合表现选择出6个优良家系。     

Responses of Pinus massoniana and Pinus taeda to freezing in temperate forests in central China

Abstract

Masson pine (Pinus massoniana Lamb.), a native species widely distributed in temperate forests in central China, and Loblolly pine (Pinus taeda L.), an exotic tree species introduced to China from southeastern United States, are dominant evergreen conifers that play a pivotal role in maintaining forest structure and functions for the region. We examined the effects of freezing on these species with chlorophyll fluorescence and electrolyte leakage using both field- and laboratory-based experiments in September 2009 and January 2010, respectively. We found that freezing could cause a greater impact on the Loblolly pine than the Masson pine. Although the two species showed similar values of F _v /F _m and electrolyte leakage before freezing, the Masson pine needles showed lower F _v /F _m and higher electrolyte leakage ratios than those of the Loblolly pine when treated in low temperatures (?15 to 0°C). We also found that cold-acclimation was crucial for both species to adapt to low temperatures with the F _v /F _m ratio decreased approximately by 80% in the first freezing hour for the non-acclimated needles of both species while the cold-acclimated needles showed little changes in the F _v /F _m ratio. This finding is also supported by our measurements of electrolyte leakage. These results suggest that the Loblolly pine could be more susceptible to freezing damages than the Masson pine in central China.     

福建省火炬松造林密度试验

在火炬松世行造林试验中,设计了4种密度,结果表明,不同密度对火炬松6年生林分的树高无显著影响,对6年生火炬松的胸径、材积、蓄积的影响达显著水平,对14年生火炬松的树高、胸径、材积、蓄积的影响均达极显著水平；不同密度、林龄火炬松各器官生物量的分配规律为：树干＞树根＞树枝＞树叶,各器官生物量的分配比例相对稳定。     

火炬松与马尾松混交造林效果分析

通过对火炬松与马尾松混交造林成效的全面调查,分析不同坡向和坡位对火炬松与马尾松生长量的影响及其树种生长规律之间的差异,结果表明：在相同立地质量等级和相同经营措施条件下,坡向以半阳坡的火炬松和马尾松生长量最大,林分总蓄积量达157.521 m3/hm2,阳坡次之,阴坡最小;坡位以下坡的火炬松和马尾松生长量最大,林分总蓄积量达170.795 m3/hm2,中坡次之,上坡最小。火炬松的平均胸径连年生长量达0.97 cm,比马尾松高出6.4%,平均树高连年生长量达0.56 m,低于马尾松10.8%,平均单株材积连年生长量达0.135 2 m3,略高于马尾松0.6%。因而,火炬松适宜当地造林。     

湿地松、火炬松育苗新方式的改进试验——芽苗移栽工具打孔器的创造和应用

报道了湿地松、火炬松育苗新方式的改进—芽苗移栽工具打孔器的创造和应用,不仅比常规播种育苗省工,而且种子利用率、苗木出圃率及苗木质量均普遍提高,每0.07hm~2育苗可增加经济收入1900多元,在国外松育苗地区具有广阔的应用前途。     

鲁山县火炬松造林技术探讨

通过几年的育苗和造林试验,总结出了火炬松在北部分界上造林的关键技术措施和方法。