Pure Alder Research Articles

The Impact of Season on Productivity and Time Consumption in Timber Harvesting from Young Alder Stands in Lowland Poland

The purpose of this study was to establish the impact of season on productivity, labour consumption, and working time structure during timber harvesting from young alder stands (Alnus glutinosa Gaertn.). An early thinning process was performed in summer and winter in pure alder stands (38 and 40 years old) in the Płaska Forest Division (NE Poland). The felling and processing operations were performed by experienced loggers using the cut-to-length (CTL) system, and forwarding with manual loading and unloading involved the use of a Zetor 7045 (65 HP) farming tractor and trailer. In both summer and winter, the loggers spent most of their labour time on felling trees (approx. 23%) and bucking (approx. 36%). Assistant loggers spent most of their time stacking logs (49.2% in summer and 58% in winter). The most time-consuming activities in forwarding were loading, unloading, and transportation. The average time consumption of tree felling and processing amounted to 0.36 ± 0.11 h/m3; that of forwarding was lower, at 0.24 ± 0.07 h/m3. No statistically significant differences in the labour consumption of tree felling were identified between winter and summer (p = 0.863). For forwarding, labour consumption was significantly higher in winter (0.28 h/m3) than in summer (0.19 h/m3, p = 0.001). Average productivity was 3.02 ± 1.09 m3/h for tree felling and 4.76 ± 1.80 m3/h for forwarding. The productivity of felling was similar in winter (2.83 m3/h) and in summer (3.22 m3/h). For forwarding, productivity was significantly higher in summer (5.70 m3/h) than in winter (3.81 m3/h, p < 0.01).

Лісівничо-таксаційна характеристика насаджень у вольєрах Західного Полісся

Досліджено лісівничо-таксаційну структуру лісових насаджень вольєрів Західного Полісся. У межах регіону функціонує 24 вольєри загальною площею 1524,1 га. Встановлено, що за структурою це 1272,7 га території лісового фонду та 251,4 га польові угіддя. У межах вольєрів виділено 21 тип лісу. Боровий комплекс представлений А1С, А2С, А3С, А4С та А4СО (111,3 га). У суборових умовах серед 5 типів лісу (В2ДС, В3ДС, В4ДС, В5БС, В5БСО) домінує В3ДС – 245,5 га або 21,7 % від загальної площі вкритих лісовою рослинністю земель. Сугруди представлені 11 типами лісу (С2ГД, С2ГДС, С2ГСД, С3ГД, С3ГДС, С3ГСД, С3ЯГС, С4ГДС, С4Влч, С4ВлО, С5Влч). Домінуючим є С4Влч (303,6 га або 26,8 %). Ще 2 типи лісу займають значні площі, а саме: С3ГДС (159,4 га) та С2ГДС (78,7 га). У вольєрах переважають мішані насадження – 396,2 га (35,0 %). Серед чистих найбільшу площу займають соснові насадження – 359,3 га (31,7 %). Площі чистих вільхових та березових насаджень становлять відповідно 255,7 га (22,6 %) та 113,3 га (10,0 %). Загалом у вольєрах переважають середньовікові насадження (463,0 га або 40,9 %). Повнота насаджень змінюється від 0,31 до 0,9. Середня повнота становить 0,71. Деревостани у вольєрах зростають за сімома класами бонітету (від Іb до V). Деревостани зростають за І (514,9 га), Іа (167,4 га) та ІІ (334,0 га) класами бонітету. Серед мішаних насаджень переважають середньовікові деревостани (44,0 % або 174,3 га). Повнота мішаних насаджень змінюється від 0,42 до 0,93, а середня становить 0,70. Деревостани зростають за Іа – ІІІ класами бонітетів. Найпоширенішими є Іа (61,3 га), І (168,1 га) та ІІ (117,7 га).

Admixture of alder (Alnus formosana) litter can improve the decomposition of eucalyptus (Eucalyptus grandis) litter

The slow nutrient turnover of eucalyptus (Eucalyptus grandis) plantations has been well documented. To examine whether the admixture of alder (Alnus formosana) litter could improve the decomposition of eucalyptus litter, a field litterbag experiment was conducted on a new eucalyptus plantation in southwestern China. We investigated the mass loss rate from an alder and eucalyptus foliar litter mixture every half month from May 1st to October 1st, 2009. Five mixture proportions were examined: pure eucalyptus litter (10E), 70% eucalyptus litter mixed with 30% alder litter (7E:3A), 50% eucalyptus litter mixed with 50% alder litter (5E:5A), 30% eucalyptus litter mixed with 70% alder litter (3E:7A) and pure alder litter (10A). Over 169 days of decomposition, approximately 79.22%, 70.23%, 62.82%, 49.95% and 48.59% of mass was lost from the 3E:7A, 10A, 5E:5A, 7E:3A and 10E litter mixtures, respectively. Compared with pure eucalyptus litter, 3E:7A, 10A, 5E:5A and 7E:3A litter mixtures increased 63.04%, 44.54%, 29.29% and 2.80% of accumulated mass loss. The admixture of alder litter can significantly improve eucalyptus litter decomposition, and a small proportion of eucalyptus litter (3E:7A) may also promote alder litter decomposition. As the decomposition proceeded, the litter mixture displayed exactly additive effects in the initial stage and positive non-additive effects in the middle stage. However, negative non-additive effects were detected in the 7E:3A litter mixture in the later stage, although positive non-additive effects were maintained throughout decomposition in the 5E:5A and 3E:7A mixtures. Compared to pure eucalyptus litter, mixtures containing alder litter presented increased microbial biomass carbon and bacterial DGGE (Denaturing Gradient Gel Electrophoresis) bands, but the litter mixture decomposition relied more on microbial biomass than on microbial diversity. The results imply that alder litter can improve material cycling on eucalyptus plantations and that alder could be a potential species for mixed planting with eucalyptus.

Red alder ( Alnus rubra) alters community-level soil microbial function in conifer forests of the Pacific Northwest, USA

Nitrogen-fixing tree species have been shown to improve site fertility and increase N transformation rates, but the influence of N-fixing plants on the soil microbial community as a whole is largely unknown. We used patterns of individual carbon-source utilization and enzyme activities to assess the relative effects of N-fixing red alder on the soil microbial community in three adjacent stands (pure conifer, mixed alder-conifer, and pure alder) of a highly productive coastal Oregon forest where the density of red alder has been experimentally manipulated for over 65 years. Two major patterns were revealed: (1) bacterial and fungal carbon-source utilization patterns in soil from pure conifer stands were significantly different from both pure alder soils and mixed conifer-alder soils, while there was no difference in substrate utilization patterns between soils from the mixed alder-conifer and pure alder stands; and (2) the activities of nine extracellular enzymes involved in ligno-cellulose degradation and the mineralization of organic nitrogen, phosphate, and sulfate compounds were all significantly greater in pure alder soils compared to either pure conifer or mixed conifer-alder soils. Our results show that, in addition to an overall increase in soil fertility, microbial biomass, and microbial activity, the presence of N-fixing red alder significantly alters the physiological profile of the microbial community-even in an ecosystem already of high N status.

Seven decades of stand development in mixed and pure stands of conifers and nitrogen-fixing red alder

Early insights on the effects of N2-fixing red alder (Alnus rubra Bong.) on conifer forests came largely from two case studies dating from the 1920s at Wind River, Washington (low soil N), and Cascade Head, Oregon (high soil N). These classic experiments were remeasured after 70 years of stand development. The pure conifer stand at Wind River showed near-zero net increment in stem mass for the past 20 years, with stem mass remaining near 120 Mg/ha. Conifer stem mass in the mixed stand continued to increase at 4.5 Mg·ha–1·year–1, reaching 230 Mg/ha at age 72. The alder mass declined over this period from about 70 Mg/ha near age 50 to just 10 Mg/ha at age 72 as a result of increasing dominance of tall Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. The pure conifer plot at Cascade Head reached a stem mass of 600 Mg/ha at age 74 years compared with 312 Mg/ha in the mixed stand (conifers, 200 Mg/ha; alder, 112 Mg/ha) and 173 Mg/ha in the pure alder plot. The long-term impacts of alder appeared to remain very strong after seven decades, greatly increasing ecosystem productivity at the N-poor Wind River site and reducing productivity at the N-rich Cascade Head site.

Influence of red alder on soil nitrogen transformations in two conifer forests of contrasting productivity

We conducted laboratory studies to determine the effects of red alder ( Alnus rubra Bong.) on soil N transformations and N availability indices at two conifer forest sites of contrasting productivity. The inclusion of red alder in conifer forests significantly increased gross rates of N mineralization, N immobilization, nitrification and NO 3 − immobilization, and the effects of alder were generally similar for soils from low- and high-productivity sites. However, the addition of alder to the conifer stand at the high productivity site increased gross N mineralization and immobilization processes more than at the low productivity site. At both sites, gross N and NO 3 − production were enhanced by alder more than gross N immobilization processes, leading to higher rates of net N mineralization and nitrification. At the fertile site, most microbial N assimilation occurred from the NO 3 − pool, compared with less than half at the infertile site (none as NO 3 − in the less productive pure conifer stand). Heterotrophic nitrification (as indicated by a lack of C 2H 2 inhibition) accounted for 65–72% of the gross nitrification in all stands that exhibited nitrification (no nitrification was detected in the pure conifer stand at the infertile site). The inclusion of red alder had no effect on the proportion of total nitrification that was heterotrophic, despite the lower soil pH in mixed alder-conifer stands compared to conifer stands. Gross rates of N mineralization correlated well with both autotrophic and heterotrophic nitrification across all soils. Gross N mineralization may be a good index of NH 4 + availability to autotrophic nitrifiers, as well as the quality of organic N as a substrate for heterotrophic nitrification. Most estimates of microbial biomass and activity, N availability and N transformation rates were significantly correlated with each other. In general, gross N transformations were better correlated with other indices of N availability and microbial activity than estimates of net N transformations. Similar N cycling rates and microbial biomass N pool sizes in pure alder and adjacent alder-conifer stands at the fertile site suggest that continued inputs of N via symbiotic N-fixation by red alder in coniferous forest stands can lead to the elimination of N-limitation to forest ecosystem production.

Alders increase soil phosphorus availability in a Douglas-fir plantation

The effect of red alder (Alnusrubra Bong.) on soil phosphorus (P) availability in conifer forests of the Pacific Northwest has been the focus of several recent studies. One study at the Thompson Research Center in Washington State, found Bray No. 2 extractable P to be lower in soils under pure alder than in soils under adjacent stands of pure conifer. The Thompson study, and others in forests of the Northwest, have also found that the quantity of P in aboveground litter fall is greater for conifer stands mixed with alder than in adjacent pure conifer stands, suggesting equal or greater soil P availability under the influence of alder. We assessed the effect of low densities of red alder on soil P, using a modified Hedley sequential P fractionation scheme, in a Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantation in coastal Oregon. We determined that soils under plots with 190 alder stems/ha and 740 Douglas-fir stems/ha had greater inorganic P availability than pure Douglas-fir plots (740 stems/ha). Inorganic P fractions, sequentially extracted from soils at 0–0.15 m depths by anion exchange resins, by sodium hydroxide, and by hydrochloric acid, were 65–225% greater in plots with alder. Soil phosphatase activity was nearly three times greater in plots mixed with alder. No significant pH differences between the treatments were found. We conclude that red alder appears to increase the availability of soil P at our site, but note that increased P supplies may not prevent a P limitation on productivity for either alder or conifers.

Nutrient relations in coppiced black cottonwood and red alder

Two-year-old coppice of black cottonwood and red alder, grown in pure culture and in mixture, were compared using terminal twigs and leafless shoots harvested in the winter. Terminal twigs were taken with buds intact; they were about 15 cm long. Leafless shoot samples included all above-ground components. In pure culture, dry weights of the leafless shoots per plant were similar for the two species. In mixture with alder, however, weight of the cottonwood plants was enhanced and that of alder was reduced, but neither response was statistically significant. Nutrient concentration, content per plant, and utilization varied by the plant tissues analyzed, cultural treatment (purevs. mixed), and species. In general, nutrient concentrations were higher in the terminal twigs than in the leafless shoots of both species. Cultural treatment did not significantly affect nutrient concentration in cottonwood twigs or in the leafless shoots of either species. Concentrations of N and Fe were significantly higher and those of Mn were lower in twigs of mixed alder than in twigs of pure alder. Twigs of cottonwood were significantly higher than those of alder in concentration of P and Zn, and lower in N, Mn, and Cu. Compared with alder, cottonwood leafless shoots were significantly higher in concentration of Ca, but lower in N, S, Cu, and Mn. With few exceptions, nutrient content was highest in the shoots of the large plants of mixed cottonwood, intermediate in medium-sized pure cottonwood and pure alder, and lowest in the small mixed alder. Cottonwood was significantly more efficient than alder in use of N, S, and Cu, and less efficient in use of Ca. Some of the differences between cultural treatments and species may be associated directly or indirectly with the N2-fixing ability of red alder. Mixed culture of the two species appears promising because of the increased growth of cottonwood. Planted separately in pure culture, the choice between cottonwood and alder may be determined, in part, by the nutritional status of the soil where plantations are established.

A study of nodulation and nitrogen fixation of alder on the purplish soils in China

The alder has a perennial nodule cluster. The nodule amount on the roots increases with tree age. The N2-fixing activity of nodules decreases with nodule age. Purple coloured soils with various soil pHs and CaCO3 contents are, in the main, the ones which influence nodulation and N2-fixing. Higher N2-fixing capacity existed in the neutral and low calcium soils. High calcium soils and acid soils can restrain nodulation and the N2-fixing rate significantly. On the slope, where calcarous light loams are found, the annual nitrogen fixation capacity of alder and cypress mixed plantations, less than 10 years old, is 16 or 17 kg/ha yr, but in the valley, a pure alder plantation can reach 40 kg/ha yr.

Nitrogen cycling in dense plantings of hybrid poplar and black alder

Nitrogen cycling was studied during the third growing season in pure and mixed plantings (33×33 cm spacing) of hybrid poplar and black alder in southeastern Canada. After 3 years, hybrid poplar growth and N content of living tissues in a plot and of individual hybrid poplar plants increased with the proportion of black alder in a planting. No differences were detected among N contents of individual alder plants regardless of plot treatment. Black alder allocated a larger portion of its N to roots than hybrid poplar. Symbiotic nitrogen fixation was estimated to account for 80% of the nitrogen in aboveground alder tissues in the pure treatment using natural15N dilution. N return in leaf litter was estimated to be 70kg ha−1 in the pure alder treatment and decreased to a minimum of 20 kg ha−1 in the pure hybrid poplar plots. No difference was detected among treatments for throughfall N content. Nitrogen concentration in roots and leaf litterfall of black alder was higher than hybrid poplar. Significant soil N accretion occurred in mixed plantings containing two alders to one poplar and pure black alder plantings. Nitrogen availability (NO3−N) increased with the amount of black alder in a plot. Results suggest that the early increase in nitrogen accumulation of hybrid poplar in mixed treatments can be attributed to an increase of total soil N availability resulting from the input of large amounts of N from easily mineralizable alder tissue.

Growth, nitrogen accumulation, and symbiotic dinitrogen fixation in pure and mixed plantings of hybrid poplar and black alder

Growth and N accumulation were assessed in pure and mixed plantings (2 years old) of hybrid poplar and black alder in southern Quebec. Symbiotic dinitrogen fixation was evaluated by natural15N dilution. Growth of hybrid poplar plants and N accumulation in their tissues increased with their decreasing contribution to species ratio whereas no differences among treatments were measured for black alder. Yield and N content per hectare of aboveground components increased with the proportion of black alder in the plantation. Symbiotic dinitrogen fixation was estimated at 68% of alder nitrogen in both pure and mixed treatments. The maximum rate of N-fixation was 53kg ha−1 yr−1 in pure alder plots. The amount of nitrogen accumulated in entire plants of black alder from symbiotic fixation could be sufficient to balance the N export in harvested stems and branches of short-rotation plantations containing at least 33% of alder.

N2 (C2 H2 )ASE ACTIVITY BY ALNUS INCANA SSP. RUGOSA (BETULACEAE) IN THE NORTHERN HARDWOOD FOREST.

Field assays of N2 (C2 H2 )ase activity were performed with intact nodules from a pure alder site (alder) and a mixed alder-aspen site (aspen). Assays were performed between 12 June and 12 August 1980 and in May 1981. N2 (C2 H2 )ase rates are expressed as g N g nodule oven-dry wt-1 hr-1 (g N g-1 hr-1 ). Diurnal N2 (C2 H2 )ase activity showed an increase in both sites between 0600 and midday, then decreased to a low by 1800. Nighttime activity in the May 1981 assay was approximately 25% of the daytime peak. Mean (±SE) 1200 hr N2 (C2 H2 )ase activity (μg N g-1 hr-1 ) for all sizes in the alder stand rose from 24.56 ± 6.56 on 12 June to 73.96 ± 28.37 on 26 June and declined to 9.20 ± 2.56 by 12 August. In the aspen stand activity decreased from the 12 June rate of 21.81 ± 4.59 to 3.64 ± 1.87 on 24 July but then increased to 30.00 ± 7.39 by 12 August. Based on diurnal assays, the seasonal mean N influx (μg N g-1 hr-1 ) is statistically higher (P 0.05) in the alder stand with a value of 26.70 compared to 14.63 in the aspen stand. Small size class shrubs had significantly higher (P < 0.05) N2 (C2 H2 )ase activity (μg N g-1 hr-1 ) in diurnal assays than medium or large class shrubs. The estimated mean (±SE) N2 (C2 H2 )ase activity (mg N g-1 season-1 ) for all sizes was 44.4 ± 18.6 in the alder stand compared to 16.2 ± 5.2 in the aspen stand. Nodule excavations showed the g shrub-1 in the alder stand to be 16.48 ± 10.29, 38.57 ± 12.34 and 29.11 ± 7.15 for small, medium and large size shrubs and 12.73 ± 3.23, 28.21 ± 4.36 and 56.45 ± 16.23 for respective sizes in the aspen stand. Seasonal N influx was 4.69 kg ha-1 in the alder stand and 0.84 kg ha-1 in the aspen stand, representing 17.9% of the alder stand. Nitrogen feedback inhibition from uric acid-N influx and allelochemic interference from aspen are discussed as explanations for the differences in N influx in the two stands.

N 2 (C 2 H 2 )Ase Activity by Alnus incana ssp. Rugosa (Betulaceae) in the Northern Hardwood Forest

Field assays of N2(C2H2)ase activity were performed with intact nodules from a pure alder site (alder) and a mixed alder-aspen site (aspen). Assays were performed between 12 June and 12 August 1980 and in May 1981. N2(C2H2)ase rates are expressed as g N g nodule oven-dry wt−1 hr−1 (g N g−1 hr−1). Diurnal N2(C2H2)ase activity showed an increase in both sites between 0600 and midday, then decreased to a low by 1800. Nighttime activity in the May 1981 assay was approximately 25% of the daytime peak. Mean (±SE) 1200 hr N2(C2H2)ase activity (μg N g−1 hr−1) for all sizes in the alder stand rose from 24.56 ± 6.56 on 12 June to 73.96 ± 28.37 on 26 June and declined to 9.20 ± 2.56 by 12 August. In the aspen stand activity decreased from the 12 June rate of 21.81 ± 4.59 to 3.64 ± 1.87 on 24 July but then increased to 30.00 ± 7.39 by 12 August. Based on diurnal assays, the seasonal mean N influx (μg N g−1 hr−1) is statistically higher (P 0.05) in the alder stand with a value of 26.70 compared to 14.63 in the aspen stand. Small size class shrubs had significantly higher (P < 0.05) N2(C2H2)ase activity (μg N g−1 hr−1) in diurnal assays than medium or large class shrubs. The estimated mean (±SE) N2(C2H2)ase activity (mg N g−1 season−1) for all sizes was 44.4 ± 18.6 in the alder stand compared to 16.2 ± 5.2 in the aspen stand. Nodule excavations showed the g shrub−1 in the alder stand to be 16.48 ± 10.29, 38.57 ± 12.34 and 29.11 ± 7.15 for small, medium and large size shrubs and 12.73 ± 3.23, 28.21 ± 4.36 and 56.45 ± 16.23 for respective sizes in the aspen stand. Seasonal N influx was 4.69 kg ha−1 in the alder stand and 0.84 kg ha−1 in the aspen stand, representing 17.9% of the alder stand. Nitrogen feedback inhibition from uric acid-N influx and allelochemic interference from aspen are discussed as explanations for the differences in N influx in the two stands.

Growth and Nitrogen Relations of Coppiced Black Cottonwood and Red Alder in Pure and Mixed Plantings

Growth and nitrogen status were assessed in pure and mixed plantings of black cottonwood and red alder. Annual dry-matter production of 2-yr-old coppice (stump sprouting) in the mixed plots was higher than production in pure cultures of cottonwood and alder. Twigs of cottonwood from mixed plantings contained 18% more nitrogen than twigs from pure plots. Soil collected in the mixed cottonwood-alder and pure alder cultures contained, respectively, 9% and 23% more nitrogen than soil from the pure cottonwood planting. For the upper 15 cm of mineral soil, average annual nitrogen accretion under the mixed stand was estimated at 32 kg/ha and under pure alder, 80 kg/ha. The beneficial effects of red alder in pure and mixed stands, obtained in such a short time, may have application for silage cellulose production, other short-rotation forest systems, and for proposed "biomass farms for energy."

Comparison of soil microfungi in 40-year-old stands of pure alder, pure conifer, and alder-conifer mixtures

The species composition of soil microfungal populations in adjacent stands of red alder Alnus rubra, conifers Pseudotsuga menziesii, Tsuga heterophylla, and Picea sitchensis, and mixed alder conifer correlated strongly with the dominant vascular vegetation. A total of 92 species were isolated: 55 from the alder stand; 45 from the conifers; and 46 from the mixed alder-conifer, with few species (16.7, and 5 in the three plots, respectively) reaching average frequencies of 50 per cent or higher. Penicillium nigricans, Aureobasidiiim pullulans, Cephalosporium curtipes, and Cladosporium herbarium were present with high frequency at all sites. Penicillium daleae, which occurred with a frequency of 83 per cent in alder soil, appears to be a rare fungus elsewhere. There was little difference in species composition among soil horizons within a stand.