Pinus Nigra Var Research Articles

The transformation of conifer forests in Britain — regeneration, gap size and silvicultural systems

There are about 1.5 Mha of conifer high forest in Great Britain composed almost entirely of even-aged plantations of non-native species established since 1900. Recent changes in forest policy require managers to introduce alternative silvicultural systems to clear-felling into windfirm conifer plantations to provide greater structural diversity and so enhance aesthetic, conservation and environmental benefits. There are around 500–750 kha of British forests established on sites which are sufficiently windfirm to be affected by this requirement but only 10–20 kha that are being managed under an appropriate silvicultural system. Expanding the area in the latter category will confront managers and researchers with major ecological, silvicultural and practical challenges. The process of transformation from uniform to irregular stands is best achieved using natural regeneration, except where other species or genotypes are desired. The start of transformation must await adequate seed production which will probably not occur before 30 years of age for the four major conifer species; Sitka spruce ( Picea sitchensis (Bong.) Carr.), Scots pine ( Pinus sylvestris L.), Corsican pine ( Pinus nigra var. maritima (Ait.) Melville), and Douglas fir ( Pseudotsuga menziesii (Mirb.) Franco) as well as a number of minor species. Once this age has been reached, manipulation of the canopy can create suitable microclimates for seedling germination and growth. Suitable conditions depend upon interacting ecological factors, the most important of which is the light climate at ground level. Because of the relative shade intolerance of the major tree species and the lower irradiance and greater cloudiness in Britain, appropriate gap sizes for regeneration may be quite large. Minimum gap sizes are usefully defined by the ratio of gap diameter to height of surrounding trees ( d/ h). Proposed d/ h ratios range from >2.0 for Scots and Corsican pines, 1–2 for Sitka spruce and Douglas fir to 1.0 or less for more shade-tolerant species (e.g. Picea abies, some Abies spp., Tsuga heterophylla). Unless greater use is made of these shade-tolerant species, it appears that silvicultural systems such as single stem selection will be inappropriate and more emphasis should be given to group selection and irregular shelterwood systems. Given the limited experience of irregular systems in Britain, it is probable that trials of transformation will be confined initially to windfirm areas of high amenity, conservation or heritage value.

Effects of rooting and tree growth of selected woodland species on cap integrity in a mineral capped landfill site.

The above and below ground growth of three tree species (Alnus glutinosa, Pinus nigra var. maritima and Acer pseudoplatanus) was studied on a containment landfill site at Waterford, Hertfordshire, UK. Tree root architecture was studied using soil inspection pits excavated next to 12 trees of each species and mapped in detail. Tree height was related to soil thickness over the compacted mineral cap. No roots entered the cap where soil thickness was 1.3 m, but a few roots, especially of alder, were observed within it when the soil cover was 1.0 m or less. Micromorphological analysis of undisturbed samples of the mineral cap suggested that roots exploited weaknesses in the cap rather than actively causing penetration into it. Alder roots were more tolerant of anaerobic conditions within the cap than the other species examined. The results confirm that mineral caps should be covered by 1.5 m of soil or soil-forming material if tree establishment is intended over a restored landfill site, unless protected by other parts of a composite capping system.

Particulate pollution capture by urban trees: effect of species and windspeed

SummaryParticulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. The use of trees to reduce the effects of these pollutants has been addressed in the literature, but has rarely been quantified. The aim of the present study was to quantify the effectiveness of five tree species − pine (Pinus nigra var. maritima), cypress ( × Cupressocyparis leylandii), maple (Acer campestre), whitebeam (Sorbus intermedia), poplar (Populus deltoides × trichocarpa‘Beaupré’) − in capturing pollutant particles. This was achieved by exposing them to NaCl droplets of approximately 1 μm diameter at a range of windspeeds in two windtunnels. The deposition velocity (Vg) and particle trapping efficiency (Cp) were calculated from these exposures. In addition, a variable dependent on foliage structure [Stokes number (St)] was correlated with Cp to gauge the effect of tree morphology on particle capture. Maximum Cp values ranged from 2.8% for P. nigra, to 0.12% and 0.06% for P. trichocarpa×deltoides and A. campertre, respectively. The finer, more complex structure of the foliage of the two conifers (P. nigra and C. leylandii) explained their much greater effectiveness at capturing particles. The data presented here will be used to model the effectiveness of tree planting schemes in improving urban air quality by capturing pollutant particles.

ACC oxidase is found in seedlings of two (Coniferales, Gnetales) of the four gymnosperm orders

Leaf material and seedlings of species representing all gymnosperm orders were tested for 1‐aminocyclopropane‐1‐carboxylate (ACC) oxidase activity. Seedlings of Pinus nigra, Pinus radiata, Pseudotsuga menziesii, Cupressocyparis leylandii, Ephedra major and E. nevadensis showed high level in vitro ACC oxidase activity. The enzyme from seedlings of Pinus nigra var. nigra (Arnold) was shown to resemble the angiosperm enzyme in a requirement for ascorbate, carbon dioxide and Fe(II). In contrast, seedlings of Ginkgo biloba, Dioon edule, Zamia furfuraceae and Cycas revoluta showed no detectable ACC oxidase activity. Leaf material from species representing all orders of gymnosperms was also tested for ACC oxidase activity in vitro, but none could be demonstrated. The results presented here support an origin of ACC oxidase in a common ancestor of the angiosperms, Gnetales and Coniferales.

Potentials and limitations of modelling vertical distributions of root water uptake of an Austrian pine forest on a sandy soil

Root water uptake patterns are often studied with simulation models of the unsaturated soil water flow, as they are difficult to measure directly. Calibration of these models is not straightforward and causes uncertainties in simulated uptake distributions. In this paper we study how uncertainties in the calibration of the SWIF model affect uncertainty intervals in simulated uptake patterns of an Austrian pine stand (Pinus nigra var. nigra) on a sandy soil. After calibrating and validating SWIF with a large data set of more than 125 000 measured soil water contents over a three year period, uncertainty ranges in simulated soil water dynamics and root water uptake distributions were estimated with a Monte Carlo analysis. In general, uncertainties in root uptake patterns were small (typically <2 10−4 m3 m−3 day−1) and were higher for trees with a shallow rooting system (0·8 m) than for trees with a deep rooting system (2·5 m). Uncertainties arose mainly from uncertainties in simulated soil water fluxes and from variations in the reduction of uptake during periods of drought. Uncertainties in soil water contents were far higher (typically 0·01 m3 m−3) than uncertainties in uptake, illustrating that uncertainties in uptake parameters and those in the distribution of water uptake hardly affect the modelling of soil water dynamics. Root water uptake models should therefore be validated against measured uptake distributions, which can be determined on sandy soils during dry periods with a high water use when soil fluxes are negligible to uptake. Copyright © 2000 John Wiley & Sons, Ltd.

Establishment and early growth of different plant types of Corsican pine (Pinus nigra var. maritima) on four sites in Thetford Forest

Summary The field performance of six different plant types of Corsican pine (Pinus nigra var. maritima (Ait.) Melville) was compared over the first 4 years after outplanting at four sites in Thetford Forest, East Anglia. The stock types differed in size, age and method of production and included conventional 1-year-old container seedlings raised in Japanese Paper Pots and Rigipots, 1 1 ⁄2- and 2-year old seedlings raised in Japanese Paper Pots, as well as 2-year-old bare-root seedlings which either had or had not been undercut. Survival was high (> 87 per cent) for all types except the non-undercut 2-year-old bare-root seedlings. Height and stem diameter growth were generally low during the first year after planting, but by the end of the second year there were significant differences between individual plant types and sites. Analysis of height increments in the second year suggested that the 1 1 ⁄2-year-old container seedlings raised in paper pots had recovered from planting check, whereas other stock types had not. However, average increments were not great enough to allow these 1 1 ⁄2-year-old seedlings to overtake 2-year-old seedlings which were taller at planting. All stock types had apparently recovered from check in the third and fourth years after planting and were tending to grow on the same growth curve at each site with shorter seedlings producing smaller height increments. Thus initial seedling size and site factors, rather than method of production, were the most important factors determining future growth with the height advantage of taller seedlings at planting being maintained or increased in subsequent years.

Manganese and calcium nutrition of Pinus sylvestris and Pinus nigra from two different origins. II. Calcium

Summary Seedlings of Scots pine (Pinus sylvestris L.) of Greek and British origins and of black pine of Greek origin (Pinus nigra var. nigricans Host.) and Corsican pine (Pinus nigra var. maritima (Ait.) Melville) from seed collected in Britain were used to establish the growth response to both increasing levels of Ca supply in nutrient solution and to varying levels of Ca and Mn supply. Solution and tissue calcium requirements of all growth components of the pines were assessed. Maximum growth for Scots pine from British and Greek origins and for black pine from British origin were obtained at foliage Ca concentration ranges of 0.34‐1.00, 0.43‐0.87 and 0.30‐0.73 per cent respectively whereas for black pine from Greek origin no upper limit was obtained but the lower limit was 0.27 per cent. The Greek derived pines, in particular the black pine, showed higher tolerance to low and high calcium availability than the British ones. It is postulated that the difference between Greek and British pines in Ca nutrition reflects the differing dominant soil characteristics between the two countries.

The role of mechanized harvesting in the development of bluestain in pine

The influence of mechanized harvesting on the development of bluestain was assessed by comparing pine logs felled and trimmed with a chainsaw with those felled by a commercial harvesting machine. Corsican pine (Pinus nigra var maritima (Ait.) Melville) grown in the United Kingdom was cut in June and August, and the logs were assessed for bluestain 3, 6, 9, and 12 weeks after felling. Mechanically harvested logs were in two groups: maximum damage (mean amount of bark loss ~35% of total cover) and minimum damage (~12% mean bark loss). However, all mechanically harvested logs were much more susceptible to attack by bluestain fungi than chainsaw-processed logs, which typically had &lt;1% bark loss. Mechanically harvested logs had bluestain on ~10% of the surface area of sample discs compared with &lt;1% in the chainsaw-harvested logs. Little bluestain developed if bark loss was &lt;10%. The most extensive stainers were Ceratocystis coerulescens (Münch) Bakshi and Leptographium wingfieldii Morelet; other frequent bluestain fungi included Ophiostoma piceae (Münch) H. &amp; P. Sydow, Sphaeropsis sapinea (Fr.) Dyko &amp; Sutton, and a Graphium species. Bluestain bark beetle vectors were excluded from the logs, but other arthropods apparently acted as vectors. Using data from the study, a model was devised to predict of stain development following a known amount of bark damage.

Manganese and calcium nutrition of Pinus sylvestris and Pinus nigra from two different origins. I. Manganese

Seedlings of Pinus sylvestris L. grown from seed of Greek and British origins, and of Pinus nigra Arnold grown from seed of Greek black pine ( Pinus nigra var. nigricans Host.) and of Corsican pine ( Pinus nigra var. maritima (Ait.) Melv.) collected in Britain were used in determining the response to both increasing levels of Mn supply in nutrient solution and to varying rates of Mn and Ca supply. Plants were about 27 weeks old when harvested. Under the conditions used it proved impossible to induce mean foliar Mn concentration below about 70 p.p.m. but even at this some plants showed symptoms of deficiency. Maximum growth of P. sylvestris occurred at foliar Mn concentrations of 240 p.p.m. and 280 p.p.m. for the plants of Greek and British origins respectively, the ranges over which growth was 90 per cent of maximum being 84-855 and 77-1450 p.p.m.. The British origins were more tolerant of high Mn supply and high tissue concentrations of Mn than were the Greek derived plants. No significant depression of growth of P. nigra was induced at low rates of supply but upper optimum limits were identified at foliar Mn concentrations of 2100 and 1400 p.p.m. for the Greek and British sourced plants. Increasing Ca supply depressed Mn uptake but did not alter optimum foliar Mn concentrations.

The role of mechanized harvesting in the development of bluestain in pine

The influence of mechanized harvesting on the development of bluestain was assessed by comparing pine logs felled and trimmed with a chainsaw with those felled by a commercial harvesting machine. Corsican pine (Pinus nigra var maritima (Ait.) Melville) grown in the United Kingdom was cut in June and August, and the logs were assessed for bluestain 3, 6, 9, and 12 weeks after felling. Mechanically harvested logs were in two groups: maximum damage (mean amount of bark loss ~35% of total cover) and minimum damage (~12% mean bark loss). However, all mechanically harvested logs were much more susceptible to attack by bluestain fungi than chainsaw-processed logs, which typically had <1% bark loss. Mechanically harvested logs had bluestain on ~10% of the surface area of sample discs compared with <1% in the chainsaw-harvested logs. Little bluestain developed if bark loss was <10%. The most extensive stainers were Ceratocystis coerulescens (Munch) Bakshi and Leptographium wingfieldii Morelet; other frequent blues...

Optimal planting times for freshly lifted bare-rooted conifers on the North York Moors

Two-year-old Picea sitchensis (Queen Charlotte Islands and Oregon provenances), Pseudotsuga menziesii, Larix kaempferi, Larix eurolepis, Pinus sylvestris and Pinus nigra var. maritima were lifted at intervals during two winters and planted within 24 h on a nearby second rotation site. Physiological condition at planting, measured by root growth potential and fine root electrolyte leakage, and outplanting performance were significantly influenced by lifting date. There were consistent differences in the species' response to lifting date. Planting out in September resulted in poor survival. Survival of P. sitchensis lifted in October until April was >90 per cent. Pinus sylvestris and P. nigra had survivals of >90 per cent when lifted in November and January respectively until March. There was no clear pattern in P. menziesii performance. Both L. kaempferi and L. eurolepis had two periods of good survival—October and March—with significantly poorer survival and growth associated with mid-winter planting. The double peak in larch performance was closely related to root growth potential; low mid-winter establishment was associated with root growth potentials of <5 even though the nursery root systems were in excellent condition as assessed by electrolyte leakage.

Histological and histochemical detection of defence responses in pine embryos challenged in vitro with Heterobasidion annosum

SummaryEmbryos of Pinus sylvestris, Pinus nigra var. maritima and Pinus contorta were inoculated in vitro with Heterobasidion annosum and the histology and histochemistry of the host response determined. Three days after challenge, intercellular penetration of hyphae through the epidermis and into the cortex of the host species had occurred. In cells close to the invading hyphae, cell walls became thickened in all three pine species. Lignification and suberization of cell walls in the cortex was detectable in P. nigra var. maritima and P. contorta, but not in P. sylvestris. Moreover, cells in the cortex of P. nigra var. maritima and P. contorta became occluded with dense deposits staining positively for phenolic and lipidic materials. Starch grains had accumulated in host cells close to sites of penetration by day 3, and levels appeared to increase by day 6, except for tissues where heavy invasion by H. annosum had occurred. Host responses intensified between 3 and 6 days after challenge. By day 6, however, the pathogen had penetrated as far as the stele and into the developing xylem vessels. Nine days after challenge, host tissues contained abundant intra‐ and inter‐cellular hyphae, causing severe disruption and disintegration of all tissues. The utility of such in vitro systems in studies on the resistance responses of conifers to challenge with fungal pathogens is discussed.

97/00690 Energy consumption in the recovery of argon from purge gas in ammonia synthesis plant

Below-ground growth of four tree species (ash (Fraxinus excelsior L.), alder (Alnus spp.), sycamore (Acer pseudoplatanus L.) and Corsican pine (Pinus nigra var. maritima (Ait.) Melville)) was investigated on a 15-year-old containment landfill in Hertfordshire, UK. The site was restored using a variable but predictable thickness of soil-forming material over the mineral cap and this permitted a study of the relationship between soil thickness and indices of tree root growth. Tree root habit was affected by soil thickness, and the likelihood of root penetration into the cap was significantly reduced when soil cover was greater than 1.25 m. Penetration into the cap appeared to occur because bulk density was often lower than threshold values set to meet permeability criteria necessary for pollution control. The study results suggest that previously published guidance on minimum soil thickness over unprotected landfill caps (1.5 m) should be adhered to, and that risk of root penetration into the cap will be acceptable if it is.

The role of micro-arthropods in the defacement of sawn lumberby sapstain and mould fungi

Fungal sap stain, mould, and basidiomycete defacement of boards sawn from the sapwood of freshly felled logs of Corsican pine (Pinusnigra var. maritima (Aiton) Melville) was assessed during a 14-week field trial at a sawmill in southern England. The boards were placed in nonstickered stacks to reduce moisture loss, and stacks were constructed in a nest arrangement to allow experimental untreated board samples to be positioned centrally in each stack. The experimental samples were placed in plastic tanks, and the open tank faces were left either uncovered or were covered with a fine-mesh nylon screen to prevent entry of micro-arthropods. All the experimental samples were sterilized by γ-radiation prior to the tanks being installed into the board stacks. The outer casing boards, which surrounded the experimental tanks in each stack, were dip treated with a fungicide, a broad-spectrum insecticide-acaricide, a combination of the fungicide and the insecticide-acaricide, or water, which served as a control. After 8 and 14 weeks of exposure, casing boards were inspected for fungal infestation. The experimental sample boards removed from the centre of the stacks at the 8-week inspection were also assessed for fungal infestation. Boards that were accessible to arthropods (i.e., in open tanks surrounded by non-insecticide-treated boards) suffered severe sap stain. Experimental boards protected from arthropods by a mesh screen and (or) casing timbers treated with the insecticide chemical had minimal sap stain. In contrast, colonization by moulds was not reduced when either physical or chemical barriers were in place, suggesting that mould spores were mainly transmitted by air currents. Micro-arthropods were clearly implicated as primary agents of sap-stain transmission on green sawn lumber. They may also graze the moulds and therefore limit the intensity of defacement by these fungi.

Long-term partitioning of biomass and nitrogen following application of nitrogen fertilizer to Corsican pine

The effects of N fertilizer on Corsican pine (Pinusnigra var. maritima (Ait.) Melv.) were studied for 22 years. Basal area increment significantly (p &lt; 0.05) increased in response to N fertilizer for 3, 6, 11, and 13 years after applications ceased, in treatments that received 252, 504, 1008, and 1512 kg N•ha−1, respectively. Volume increment changed from a quadratic to a linear response to N level during the study period. Overall, the highest rate of N fertilizer increased the aboveground standing biomass by 42%, four-fifths of which occurred in stems. The response of crown components was variable, but there was evidence of a prolonged increase in foliage biomass due to N fertilizer. Initial retention of N within stands was sustained in the longer term, although N distribution altered. These results supported earlier predictions that the growth response to N fertilizer could be sustained through internal cycling, without increasing demands for N uptake from the soil. Increase of N within stands (over and above fertilizer inputs) was similar to estimated rates of atmospheric input, with indirect evidence of a positive feedback between increased foliage biomass and increased levels of N interception by crowns.

The effects of sewage sludge on growth and foliar and soil chemistry in pole-stage Corsican pine at Ringwood Forest, Dorset, UK

An experiment to examine the use of sewage sludge as a fertiliser for pole-stage Corsican pine (Pinusnigra var. maritima (Ait.) Melville) is described. Dominant and codominant trees responded markedly to additions of sludge at rates of 200 and 400 m3•ha−1, increasing sawlog volume by over 50% in treated plots. Foliar analyses suggest that the trees have responded to phosphorus in the sludge. The greatest impact of sludge on the soil occurred in the litter layer; concentrations of nitrogen, phosphorus, calcium, zinc, copper, cadmium, and lead were all greater compared with concentrations of untreated controls. Nevertheless, at rates of sludge application appropriate to fertilising (200 m3•ha−1), additions of heavy metals are considered small and are unlikely to cause adverse environmental effects.

Effects of ammonium and aluminium on the development and nutrition of Pinus nigra in hydroculture

Application of ammonium and aluminium to young Pinus nigra var. maritima (Ait.) Melville trees resulted in a variety of negative effects. Excess ammonium led to an increase in shoot/root ratio. The biomass of the fine roots declined, resulting in an increase of the coarse/fine root ratio. The degree of mycorrhizal infection of the roots decreased. The nitrogen content of the trees increased considerably, whereas particularly the levels of calcium magnesium, manganese and zinc decreased sharply. Excess aluminium resulted in a simultaneous reduction of root and shoot biomass, a decline of the fine root system, an increase in the coarse/fine root ratio and a decrease in the degree of mycorrhizal infection. Uptake of the divalent cations calcium, magnesium, iron, manganese and zinc was restricted substantially, The nitrogen and phosphorus contents of the trees were hardly affected, whilst the potassium content of the shoot increased and of the roots decreased. This implicates that a deteriorating fine root system has to supply water and nutrients to a more demanding shoot. In the long term, high ammonium inputs and aluminium dissolution in forest ecosystems will lead to substantial nutrient deficiencies, just as has been found in the field.

Growth intercept as an indicator of site quality for planted and natural stands of Pinus nigra var. pallasiana in Greece

Five-year intercept was found to be a reliable index in site evaluation of both planted and natural stands of black pine. Use of more than five internodes improves the precision of the site-index prediction equation, while using less than five nodal lengths gives inaccurate results. Five-year intercept starting at a point higher than breast height does not significantly improve site-index prediction.

Nitrogen productivity of some conifers

Nitrogen productivity, expressed as annual yield of foliage per unit of nitrogen in the foliage, is recommended for interpreting responses to changes in nitrogen availability. This index can be directly coupled to growth and is well suited for application in mathematical analyses of tree or forest growth dynamics. This paper demonstrates that the nitrogen productivity decreases predictably as biomass increases probably as a result of the reduction in irradiance as the canopy becomes more dense. For five species of conifers from northern latitudes (Piceaabies Karst., Pseudotsugamenziesii Mirb. Franco, Pinusnigra var. maritima (Ait.) Melv., Pinusresinosa Ait., and Pinussylvestris L.) nitrogen productivity is shown to decrease linearly with increasing needle biomass. For a particular species, these regressions allow for estimation of maximum needle biomass.

Optimum foliar nitrogen concentration in pine and its change with stand age

Levels of nitrogen in foliage associated with optimum growth of pine were determined in two hydroponic experiments in the glasshouse and two forest fertilizer experiments each designed to cover the full response range for Pinusnigra var. maritima (Ait.) Melv. During the years prior to canopy closure optimum nitrogen concentrations declined with the logarithm of tree weight, falling from 3.3% in very young seedlings to 1.5% in forest trees of 2.0–2.5 m in height. After canopy closure the level increased to about 2.0%. At all stages the concentrations associated with maximum height growth were less than those for maximum volume, weight, or diameter increment. The relationships in the forest experiments, which are on sand dunes in the north of Scotland, could be improved by including factors of rainfall during the previous August and September and of temperature in June of the same year, but this did not alter the optima. It is concluded that for diagnostic purposes critical foliar nitrogen levels must be qualified by the age or developmental stage of the trees.