Forest Ecology and Management最新文献_第2页

Tree planting outcomes after severe wildfire depend on climate, competition, and priority 严重野火后的植树结果取决于气候、竞争和优先次序

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-11 DOI: 10.1016/j.foreco.2024.122346

Quinn M. Sorenson, Derek J.N. Young, Andrew M. Latimer

With dramatic increases in both area burned and fire severity in Western North American conifer forests, the demand for postfire replanting greatly exceeds land managers’ capacity. Despite the importance of tree planting for forest recovery in many areas, it remains unclear how environmental variation and planting timing affect tree planting success relative to passive natural tree regeneration, or how to optimize limited planting resources by focusing on the right places at the right time. To address this gap, we surveyed replanting success across five fires in California Sierra Nevada mixed conifer forest that had been partially replanted with conifer species after intense wildfire. We selected these fires to contain substantial variation in environmental conditions (temperature, elevation, other topographic contrasts) and planting timing, while being as consistent as possible in postfire management. At each fire, we surveyed randomly located 400 m2 circular plots in planted and nearby unplanted areas (total 182 plots), counting seedlings by species as well as shrub cover and other environmental variables. Using mixed models to analyze the data, we found that passive natural regeneration is weaker (<50 seedlings/ha) in hotter, drier sites and that active tree planting can provide a boost (up to 200 %) to forest recovery in these sites. We also found that the timing of tree planting matters, but that the importance of timing depends on the level of competition from shrubs. In places where shrub competition is intense, tree planting is much more successful if planting occurs the year immediately following a fire, the soonest that it is usually practical to plant. In contrast, in places where shrub competition is weaker, delaying tree planting until some shrubs establish can facilitate tree seedling survival, perhaps because shrubs provide shelter from harsh conditions. We also found that tree planting was strongly associated with a higher proportion of pine seedlings, although this positive planting effect was weaker when planting happened later after fire, and was cancelled out at higher levels of shrub cover and shrub height.

随着北美西部针叶林烧毁面积和火灾严重程度的急剧增加，对火灾后重新植树的需求大大超出了土地管理者的能力。尽管植树对许多地区的森林恢复非常重要，但环境变化和植树时机如何影响植树成功率（相对于被动的自然树木再生），以及如何通过在正确的时间集中在正确的地点优化有限的植树资源，这些问题仍不清楚。为了填补这一空白，我们调查了加利福尼亚内华达山脉针叶混交林中五次火灾的补种成功率，这些森林在强烈野火后部分补种了针叶树种。我们选择的这些火场在环境条件（温度、海拔、其他地形对比）和种植时间上都有很大差异，同时在火后管理上尽可能保持一致。在每次火灾中，我们都会在已种植区和附近未种植区（共 182 个小区）随机选取 400 平方米的圆形小区进行调查，按树种统计树苗数量，并统计灌木覆盖率和其他环境变量。通过混合模型分析数据，我们发现在较热、较干燥的地点，被动的自然再生能力较弱（50 株/公顷），而在这些地点，主动植树可以促进森林恢复（最多可达 200%）。我们还发现，植树的时机很重要，但时机的重要性取决于灌木的竞争程度。在灌木竞争激烈的地方，如果在火灾后的第二年植树，植树的成功率要高得多，而在火灾后的第二年植树通常是植树的最佳时机。相反，在灌木竞争较弱的地方，推迟植树，直到一些灌木成活，可以促进树苗的存活，这可能是因为灌木可以为树苗提供庇护，使其免受恶劣环境的影响。我们还发现，植树与更高比例的松树幼苗密切相关，尽管在火灾后植树的时间较晚时，这种积极的植树效应较弱，而且在灌木覆盖率和灌木高度较高的情况下，植树效应被抵消。

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引用次数: 0

Long-term soil nutrient and understory plant responses to post-fire rehabilitation in a lodgepole pine forest 在一片落叶松林中，土壤养分和林下植物对火灾后恢复的长期反应

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-09 DOI: 10.1016/j.foreco.2024.122359

Sophia Kaiser , Timothy S. Fegel , David M. Barnard , Adam L. Mahood , Kya Sparks , Kaela K. Amundson , Michael J. Wilkins , Charles C. Rhoades

Wildfires and other disturbances play a fundamental role in regenerating lodgepole pine forests. Though severe, stand-replacing fires are typical of this ecosystem, they can have dramatic impacts on soil properties and biogeochemical processes that influence the rate and composition of vegetation recovery. Organic soil amendments are often applied to manage post-fire erosion, but they can also improve soil moisture and nutrient retention and potentially alter the trajectory of post-fire revegetation. We compared change in soil nutrients, microbial communities, and understory plant cover and composition on six burned hillslopes treated with 1) biochar (20 t ha ⁻¹), 2) wood mulch (37 t ha⁻¹), 2) biochar + mulch, and 4) an untreated control a decade after the 2010 Church’s Park fire. Wood mulch increased soil moisture and N retention the first three years following treatment. Mulch and biochar were still visible when we resampled in 2023. Mulch continued to increase soil moisture compared to unamended controls, though it had few lasting effects on soil N or cations. Conversely, biochar added alone increased dissolved organic C in soil leachate, C:N in soil and leachate, and hosted microbial communities distinct from those in mulch and combined biochar and mulch treatments. Biochar also elevated various dissolved and extractable soil N forms but reduced net nitrification. The amendments had no general effect on total graminoid, forb, or shrub cover, but had plant species-specific impacts. For example, biochar doubled cover of the dominant shrub Vaccinium scoparium, and mulch reduced cover of the most common forb (Oreochrysum parryi) by more than 50 %. The combined biochar and mulch treatment had persistent, additive effects on both soil and plant responses that exceeded impacts of the individual treatments. As seen increasingly in western North America, conifer regeneration remains scarce in the Church’s Park burn scar, and these findings suggest that mulch and biochar amendments may improve reforestation success following severe wildfires.

野火和其他干扰对落羽松森林的再生起着至关重要的作用。虽然严重的森林火灾是这一生态系统的典型特征，但它们会对土壤特性和生物地球化学过程产生巨大影响，从而影响植被恢复的速度和组成。有机土壤改良剂通常用于控制火灾后的水土流失，但它们也能改善土壤水分和养分的保持，并有可能改变火灾后植被重建的轨迹。2010 年 Church's Park 大火发生十年后，我们比较了六个烧毁山坡上土壤养分、微生物群落、林下植物覆盖率和组成的变化，这些山坡分别使用了 1) 生物炭（20 吨/公顷-1）、2) 木质覆盖物（37 吨/公顷-1）、2) 生物炭 + 覆盖物和 4) 未经处理的对照组。在处理后的头三年，木质覆盖物增加了土壤水分和氮的保持率。我们在 2023 年重新取样时，仍能看到覆盖物和生物炭。与未添加覆盖物的对照组相比，覆盖物继续增加土壤湿度，但对土壤氮或阳离子的持久影响很小。相反，单独添加的生物炭增加了土壤沥滤液中的溶解有机碳、土壤和沥滤液中的碳氮比，并产生了不同于覆盖物和生物炭与覆盖物组合处理的微生物群落。生物炭还提高了土壤中各种溶解氮和可萃取氮的含量，但降低了净硝化作用。这些改良剂对禾本科植物、禁止植物或灌木的总覆盖率没有普遍影响，但对特定植物物种有影响。例如，生物炭使主要灌木 Vaccinium scoparium 的覆盖率提高了一倍，而覆盖物则使最常见的禁草（Oreochrysum parryi）的覆盖率降低了 50% 以上。生物炭和覆盖物的综合处理对土壤和植物的反应具有持续的叠加效应，超过了单独处理的影响。正如在北美西部越来越多地看到的那样，Church's Park 烧伤疤痕中针叶林的再生仍然稀少，这些研究结果表明，覆盖物和生物炭添加剂可以提高严重野火后重新造林的成功率。

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引用次数: 0

Abundance of Taphrorychus bicolor in beech forests: Influence of forest size and optimal conditions 山毛榉林中双色鹅掌楸（Taphrorychus bicolor）的数量：森林面积和最佳条件的影响

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-09 DOI: 10.1016/j.foreco.2024.122362

Jaroslav Holuša , Ivana Henzlová , Barbora Dvořáková , Karolina Resnerová , Jan Šipoš , Otakar Holuša , Jaromír Bláha , Roman Berčák , Jiří Procházka , Jiří Trombik , Tomáš Fiala

The bark beetle Taphrorychus bicolor primarily inhabits Fagus sylvatica forests. Its populations increase after periods of drought. Due to the limited knowledge of factors affecting its abundance, we conducted a large-scale sampling. Beetles were captured using three Theysohn traps lured with bicolorin at 26 study sites in mature homogeneous beech forests distributed throughout the Czech Republic. The traps were checked, and beetles were sampled weekly or biweekly in 2022. Using Generalized Linear Mixed Models (GLMMs), the impact of selected environmental and management variables on the abundance of T. bicolor was analyzed. The species occurs at elevations ranging from 150 m a.s.l. to 1300 m a.s.l. throughout the Czech Republic. This represents its entire host range, e.g., beech, although in the lowest elevations it is also found on other deciduous trees. In 2022, the flight activity lasted from late April to early September, and two generations were recorded, with the filial generation starting to fly in late June. In many study sites, more than 10,000 beetles were captured per trap. The number of females trapped was higher than males, consistent with the species' polygamous strategy, where females move toward increasing concentrations of pheromones. The number of beetles in the traps was influenced by elevation, with the highest abundance observed at around 600 m a.s.l. Abundances were higher in areas with more extensive beech forest complexes. Lower beetle abundances were found in stands where the studied forest bordered with meadows, pastures, or crop fields, indicating the species' reluctance to fly outside the forest habitat. The abundance of the filial generation was higher when there was a larger area of beech forests within a 1000 m radius, suggesting a median dispersal flight distance of approximately 1 km for the filial generation.

树皮甲虫 Taphrorychus bicolor 主要栖息在法桐林中。干旱期过后，它的数量会增加。由于对影响其数量的因素了解有限，我们进行了大规模采样。在捷克共和国境内分布的成熟同质山毛榉林中的 26 个研究地点，我们使用三个用双色素引诱的 Theysohn 诱捕器捕捉甲虫。对诱捕器进行了检查，并在 2022 年每周或每两周对甲虫进行采样。利用广义线性混合模型（GLMMs）分析了选定环境和管理变量对双色甲虫丰度的影响。该物种分布于捷克共和国海拔 150 米至 1300 米的地区。这代表了它的整个寄主范围，如山毛榉，尽管在海拔最低的地方，它也在其他落叶树上发现。在 2022 年，其飞行活动从 4 月下旬持续到 9 月上旬，共记录到两代，其中子代从 6 月下旬开始飞行。在许多研究地点，每个诱捕器都捕获了超过 10,000 只甲虫。雌虫被捕获的数量高于雄虫，这与该物种的一夫多妻策略一致，即雌虫向信息素浓度越来越高的地方移动。诱捕器中的甲虫数量受海拔高度的影响，海拔 600 米左右的地区甲虫数量最高。在所研究的森林与草地、牧场或庄稼地接壤的林分中，甲虫的丰度较低，这表明该物种不愿飞出森林栖息地。当半径 1000 米范围内的山毛榉林面积较大时，子代甲虫的丰度较高，这表明子代甲虫的中位扩散飞行距离约为 1 千米。

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引用次数: 0

Past disturbances shape present tree size distribution in European temperate primary beech-dominated forests 过去的干扰决定了欧洲温带以山毛榉为主的原始森林目前的树木大小分布

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-05 DOI: 10.1016/j.foreco.2024.122364

Ruffy M. Rodrigo , Joseph L. Pettit , Pavel Janda , Jakob Pavlin , Dheeraj Ralhan , Daniel Kozak , Radim Matula , William Marchand , Radek Bače , Martin Dušátko , Tomás Kníř , Michal Frankovič , Martin Mikoláš , Jeňýk Hofmeister , Cătălin-Constantin Roibu , Melanie Saulnier , Miroslav Svoboda

Natural disturbances play a crucial role in shaping forest structural dynamics, directly influencing stand structural heterogeneity. In European forests, disturbances occur across varying scales, from small patches to entire landscapes, significantly affecting ecosystem dynamics. However, detailed information on historical disturbances and their specific effects on forest structure, particularly tree size distributions in primary mountain forests, remains limited. With global change altering the severity and frequency of these disturbances, understanding their long-term impact has become increasingly critical for forest management and conservation. We addressed two main questions: (1) Is there variability in tree size distributions at both the plot and stand level? and (2) which specific aspects of disturbance regimes, such as severity and timing, are most influential in shaping these distributions? To address these questions, we analyzed data from 11,755 trees across 23 primary European beech forest stands in the Carpathian Mountains of Romania (139 plots) and Slovakia (99 plots). Using linear mixed-effects models, we assessed how historical disturbances have influenced current tree size distributions. Our results showed that tree size distributions across the Carpathians show variability, with the most common pattern being close to a reverse-J shape, indicative of uneven-aged forest structures. Modelling analyses revealed that disturbance severity and timing are key factors influencing present tree size distribution patterns at small scales in the Carpathian Mountains. High-severity disturbances generally result in unimodal or bimodal distributions, while low-severity disturbances are associated with reverse-J shaped patterns. Specifically, at the plot level (small scale), we observed that last disturbance severity, maximum disturbance severity, and time since the last disturbance all significantly impacted tree size distributions driving them away from a reverse-J shape. Finally, linear mixed-effects modeling revealed that disturbance severity, time since the last disturbance and the interaction between the two were the most influential factors shaping present tree size distributions. Our findings highlight the dynamic nature of forest ecosystems, emphasizing the critical role of historical disturbances in shaping present tree structure and the long-term development of forest stands.

自然干扰在形成森林结构动态方面起着至关重要的作用，直接影响林分结构的异质性。在欧洲的森林中，干扰发生在不同的范围，从小的斑块到整个景观，对生态系统的动态产生了重大影响。然而，有关历史干扰及其对森林结构（尤其是原始山林中树木大小分布）具体影响的详细信息仍然有限。随着全球变化改变了这些干扰的严重程度和频率，了解它们的长期影响对于森林管理和保护变得越来越重要。我们探讨了两个主要问题：(1) 树木大小分布在小区和林分层面是否存在变异？ (2) 干扰机制的哪些具体方面（如严重程度和时间）对这些分布的形成影响最大？为了解决这些问题，我们分析了罗马尼亚喀尔巴阡山脉（139 个地块）和斯洛伐克（99 个地块）23 个欧洲山毛榉原始森林林分中 11,755 棵树的数据。利用线性混合效应模型，我们评估了历史干扰对当前树木大小分布的影响。我们的结果表明，喀尔巴阡山脉的树木大小分布呈现出多变性，最常见的模式接近于 "反-J "形，表明森林结构年龄不均。建模分析表明，干扰的严重程度和时间是影响喀尔巴阡山脉小尺度树木大小分布模式的关键因素。高严重程度的干扰通常会导致单峰或双峰分布，而低严重程度的干扰则会导致反向的 "J "型分布。具体来说，在地块水平（小尺度）上，我们观察到最后一次干扰严重程度、最大干扰严重程度和自最后一次干扰以来的时间都会对树木大小分布产生显著影响，使其偏离反J形分布。最后，线性混合效应模型显示，干扰严重程度、自上次干扰以来的时间以及两者之间的交互作用是影响目前树木大小分布的最有影响力的因素。我们的研究结果凸显了森林生态系统的动态性质，强调了历史干扰在形成当前树木结构和林分长期发展中的关键作用。

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引用次数: 0

Making the most of native seeds: Management techniques interact with seed and seedling traits for enhancing direct seeding success 充分利用本地种子：管理技术与种子和幼苗特性相互作用，提高直接播种的成功率

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-05 DOI: 10.1016/j.foreco.2024.122353

Maxmiller Cardoso Ferreira , Daniel Luis Mascia Vieira

Direct seeding offers a cost-effective approach to large-scale restoration, but seedling establishment can vary greatly across species and regions. This study investigates how management techniques used for seed processing, site preparation, seeding, and post-seeding management interact with seed/seedling traits and influence direct seeding success. We conducted a systematic review of Brazilian direct seeding research, encompassing 26 % of global studies. We focused on paired experiments comparing management techniques against control treatments to analyze seedling establishment rates for trees, shrubs, and palms. The techniques included pre-soaking seeds, overcoming seed dormancy, seed burial, mulch application, soil fertilization, intercropping with green manure or agricultural crops, weed control, and sowing in the shade of secondary vegetation. Seed traits were fresh mass, water content, and shape, and seedling traits were functional morphology, successional guild, and vegetation guild, i.e., forest or savanna. Pre-germination treatments offered no significant benefit. Seed burial doubled establishment, and mulch application only aided unburied seeds. Organic fertilization reduced establishment for savanna species, while intercropping with green manure or crops enhanced establishment for forest species. Weed control effectiveness depended on functional traits. Mowing favored pioneers, while hoeing or herbicide application benefited large-seeded and epigeal-foliaceous-cotyledon seedlings. Pioneer species establishment was 15 % in full sun and 3 % in the shade, while shade-tolerant climax species established at 8 % in full sun and 28 % in the shade. By implementing management techniques, direct seeding success can be increased up to fourfold. This translates to a potential reduction in seed usage, the primary cost of direct seeding, by 25–75 %. These findings pave the way for cost-effective restoration efforts with improved seedling establishment rates.

直接播种为大规模恢复提供了一种具有成本效益的方法，但不同物种和地区的幼苗成活率会有很大差异。本研究调查了种子处理、场地准备、播种和播种后管理等方面的管理技术如何与种子/幼苗性状相互作用，并影响直播的成功率。我们对巴西的直播研究进行了系统回顾，涵盖了全球 26% 的研究。我们将重点放在对比管理技术与对照处理的配对实验上，以分析乔木、灌木和棕榈树的成苗率。这些技术包括预浸种、克服种子休眠、埋种、覆盖、土壤施肥、与绿肥或农作物间作、杂草控制以及在次生植被遮荫处播种。种子性状包括鲜重、含水量和形状，幼苗性状包括功能形态、演替区系和植被区系，即森林或热带草原。发芽前处理无明显益处。种子埋藏可使种子成活率提高一倍，而覆盖物的应用仅对未埋藏的种子有帮助。有机施肥降低了热带稀树草原物种的成活率，而间作绿肥或农作物则提高了森林物种的成活率。杂草控制效果取决于功能特征。刈割有利于先锋树种，而锄草或施用除草剂则有利于大粒种子和外胚叶子叶幼苗。先锋树种在全日照下的成活率为 15%，在阴凉处的成活率为 3%，而耐阴的高潮树种在全日照下的成活率为 8%，在阴凉处的成活率为 28%。通过实施管理技术，直接播种的成功率可提高四倍。这意味着种子用量（直播的主要成本）有可能减少 25-75%。这些发现为提高秧苗成活率、开展具有成本效益的恢复工作铺平了道路。

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引用次数: 0

Variations in stand structure, composition, and fuelbeds drive prescribed fire behavior during mountain longleaf pine restoration 在山地长叶松恢复过程中，林分结构、组成和火床的变化驱动着规定的用火行为

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-05 DOI: 10.1016/j.foreco.2024.122372

Collin J. Anderson , Matthew P. Weand , Heather D. Alexander , Mario Bretfeld , Nicholas Green

Across the central and eastern U.S., frequent-fire (∼ 1–5 year interval) dependent savannas, woodlands, and forests have experienced widespread ecological state shifts due to decades of fire exclusion. Without fire, mesophytes (i.e., shade-tolerant, often fire-sensitive and/or opportunistic tree species) are encroaching in the midstory, creating shady, moist understories with low flammability and reduced biodiversity through a process known as “mesophication.” Although prescribed fire is commonly used to reverse mesophication and restore fire-dependent ecosystems, fire behavior during restoration remains difficult to predict because variations in stand structure and composition and associated fuels interact to influence flammability. To better understand the mesophication mechanisms influencing fire behavior and to identify key predictors of fire behavior for the benefit of land managers, we assessed how metrics that describe fire intensity (maximum temperature, rate of spread, and residence time) and severity (fuel consumption) relate to pre-fire stand and leaf litter composition and structure. We focused on the restoration of remnant mountain longleaf pine (Pinus palustris Mill. (LLP)) stands during the dormant prescribed fire season in the Georgia Piedmont region, USA. Using Bayesian path analysis, we compared the effects of either stand or leaf litter composition and structure on fire behavior. Lower stand basal area and higher relative importance of pine and pyrophytic hardwoods (e.g., upland Quercus spp.) and associated leaf litter types were expected to increase fire intensity. Results showed that stand composition and structure significantly influenced fire behavior, but not because of their influence on litter structure (load and bulk density). Rather, leaf litter composition may better explain fire behavior than leaf litter structure. Results also suggest that simple measures of stand composition and structure alone can be used to predict fire behavior, providing a potentially useful tool for assessing restoration potential of fire-dependent ecosystems under threat of mesophication.

在美国中部和东部，由于数十年的禁火，依赖频繁用火（间隔 1-5 年）的稀树草原、林地和森林经历了广泛的生态状态转变。在没有火的情况下，中生植物（即耐阴、通常对火敏感和/或投机取巧的树种）蚕食中层，通过一个被称为 "中生化 "的过程，形成阴暗潮湿、易燃性低和生物多样性减少的林下空间。尽管通常使用规定火力来扭转中生化并恢复依赖火力的生态系统，但由于林分结构和组成的变化以及相关燃料的相互作用会影响易燃性，因此恢复过程中的火力行为仍然难以预测。为了更好地了解影响火灾行为的中生化机制，并确定火灾行为的关键预测因素，以利于土地管理者，我们评估了描述火灾强度（最高温度、蔓延速度和停留时间）和严重程度（燃料消耗）的指标与火灾前林木和落叶层组成和结构的关系。我们重点研究了山地长叶松（Pinus palustris Mill.(LLP）林分的恢复情况。通过贝叶斯路径分析，我们比较了林分或落叶组成和结构对火灾行为的影响。较低的林分基部面积和较高的松树、热解硬木（如高地柞树属）及相关落叶类型的相对重要性预计会增加火灾强度。结果表明，林分组成和结构对火灾行为有显著影响，但这并不是因为它们对落叶结构（负荷和体积密度）的影响。相反，枯落叶组成比枯落叶结构更能解释火灾行为。研究结果还表明，仅通过简单测量林分组成和结构就能预测火灾行为，这为评估面临中层化威胁的火灾依赖生态系统的恢复潜力提供了一种潜在的有用工具。

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引用次数: 0

Bentonite as substrate conditioner under different water regimes – A Eucalyptus dunnii seedling assay 膨润土作为不同水质条件下的基质调节剂--桉树幼苗试验

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-04 DOI: 10.1016/j.foreco.2024.122352

Alessandra Cunha Pessoa, Leonardo Castilho Balbinot, Luara Castilho Balbinot, Leticia Siqueira Walter, Dagma Kratz, André Carlos Auler, Antônio Carlos Nogueira

The substrate has a lot of functions in the process to develop a high-quality seedling, including the responsibility to hold water and to make the water available for the plants. A compound that can be used to hold water is bentonite. So, the research aimed to evaluate the effects of different proportions of bentonite as a substrate component under two water conditions in the production of Eucalyptus dunniii seedlings. The research was carried out in the forest seedlings nursery in Curitiba/PR - Brazil. For the treatments, bentonite substrate conditioner was used in different proportions, 0 %, 5 %, 10 %, 15 % and 20 %, in a commercial substrate (with sphagnum peat) here named as S0, S5, S10, S15 and S20 respectively, in two water regimes for the blocks. The seedlings produced with these bentonite proportions was analyzed by the height, stem diameter, dry matter (shoot, root and total), and two parameters: height/stem diameter ratio (H/SD) and Dickson Quality Index (DQI). The substrate analysis shown a contrary behavior of expected. The bentonite in the substrate for seedlings of E. dunnii did not increase water holding capacity in a linear form and the high proportion of bentonite did not improve seedling in the lower water regime, although the 5 % of bentonite gave a good results of seedlings growth, so the purpose of bentonite in the substrate to improve water holder capacity and minimize the irrigation would not be fully attended.

在培育优质秧苗的过程中，基质有很多功能，包括保持水分和为植物提供水分。膨润土就是一种可以用来保持水分的化合物。因此，研究的目的是评估在两种水质条件下，不同比例的膨润土作为基质成分对桉树幼苗培育的影响。研究在巴西库里提巴（Curitiba/PR）的林木育苗场进行。在处理过程中，膨润土基质调节剂在商品基质（含泥炭）中的使用比例不同，分别为 0%、5%、10%、15% 和 20%，分别命名为 S0、S5、S10、S15 和 S20。用这些膨润土比例培育出的幼苗的高度、茎径、干物质（芽、根和总量）以及两个参数：高度/茎径比（H/SD）和迪克森质量指数（DQI）进行了分析。基质分析结果与预期相反。虽然 5% 的膨润土能使幼苗生长良好，但高比例的膨润土并不能提高幼苗在低水位条件下的持水量，因此基质中膨润土提高持水量和减少灌溉的目的并不能完全达到。

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引用次数: 0

Effects of experimental partial harvesting regimes on forest canopy structure and complexity 试验性部分采伐制度对林冠结构和复杂性的影响

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-04 DOI: 10.1016/j.foreco.2024.122347

Brandon C. Alveshere , Christel C. Kern , Robert T. Fahey

The physical structure of forest canopies regulates numerous ecological processes and functions, and management strategies to promote specific structural features, such as high structural complexity, are increasingly desired. Partial disturbances — including partial harvests — can modify forest canopy structure, but their specific effects may be influenced by differences in characteristics such as intensity and frequency. Understanding the variable effects of silvicultural treatments on canopy structure will be essential to designing silvicultural regimes that can promote canopy structural complexity. We evaluated the effect of partial harvesting regimes on canopy structure (i.e., density, cover, height, arrangement, and heterogeneity) and complexity (as rugosity), quantified using a suite of metrics derived from portable canopy lidar, across three levels of harvesting intensity in three multi-decadal silvicultural experiments. We specifically assessed: 1) how repeated partial harvesting disturbance affected canopy structure and complexity relative to unmanipulated controls, 2) whether effects of partial harvesting differed among harvesting intensities or 3) between old- and second-growth stands, and 4) if canopy light interception differed among stands with different histories of partial harvesting disturbance. Findings indicated that canopy structure development under partial harvesting regimes differed from that of control stands, reducing vertical and canopy structural complexity at a fine (i.e., 1–6 ha treatment unit) scale, but increasing among-unit variability in canopy structure relative to controls. Variation in intensity among treatments produced relatively little distinction in fine-scale canopy structural outcomes, but the higher intensity selection harvesting regime in particular differed significantly from controls across all metrics of canopy structure. Partial harvesting affected the developmental trajectories of both old-growth and maturing, secondary forest stands, where selection-based management seemed to decrease structural features associated with old forests. Our findings suggest management regimes developed for timber goals could accommodate alternative goals that promote multi-scale canopy structural complexity across managed northern hardwood forest landscapes by adapting the timing (e.g., extending cutting intervals) and intensity (e.g., low intensity harvests) of partial harvesting to retain or develop elements of canopy complexity.

林冠的物理结构调节着许多生态过程和功能，人们越来越希望采取管理策略来促进特定的结构特征，如高度的结构复杂性。部分干扰（包括部分采伐）可以改变林冠结构，但其具体效果可能受到强度和频率等特征差异的影响。了解造林处理对树冠结构的不同影响对于设计能促进树冠结构复杂性的造林制度至关重要。我们评估了部分采伐制度对树冠结构（即密度、覆盖度、高度、排列和异质性）和复杂性（即崎岖度）的影响，这些影响是通过便携式树冠激光雷达得出的一套指标量化的，在三个十年期造林实验中的三个采伐强度等级中均有体现。我们具体评估了1）相对于未受干预的对照组，重复部分采伐干扰如何影响树冠结构和复杂性；2）不同采伐强度或 3）老生林和次生林之间，部分采伐的影响是否不同；4）不同部分采伐干扰历史的林分，树冠截光是否不同。研究结果表明，部分采伐制度下的树冠结构发展与对照林分不同，在精细（即 1-6 公顷处理单元）尺度上降低了垂直和树冠结构的复杂性，但相对于对照林分，增加了树冠结构在单元间的变异性。不同处理之间的强度差异对精细尺度冠层结构结果的影响相对较小，但在冠层结构的所有指标方面，强度较高的选择性采伐机制与对照组的差异尤其显著。部分采伐影响了古老林分和成熟次生林分的发展轨迹，其中基于选择的管理似乎减少了与古老森林相关的结构特征。我们的研究结果表明，通过调整部分采伐的时间（如延长砍伐间隔）和强度（如低强度采伐）以保留或发展树冠复杂性要素，为木材目标而制定的管理制度可以适应促进多尺度树冠结构复杂性的北方阔叶林景观管理的替代目标。

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引用次数: 0

Growth trends of loblolly pine age five or less in relation to soil type and management intensity 五龄或五龄以下小叶松的生长趋势与土壤类型和管理强度的关系

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-04 DOI: 10.1016/j.foreco.2024.122355

Christen Beasley , David R. Carter , Timothy J. Albaugh , David Enemo , Daniel S. Hong , Rachel Cook , Otávio Campoe , Rafael Rubilar

We evaluated three objectives for loblolly pine (Pinus taeda L.) trees age five or less: 1) how height growth varies by soil type and silvicultural intensity, 2) the accuracy of predicted base-age 25 site index (SI25) using age one to five heights, and 3) if height dominance exhibited early in the rotation is maintained throughout the rotation. Data from 42 sites across the southeastern United States with an array of soil textures and management intensities (optimal, intensive, and operational) were used. Management intensity and soils significantly affected tree height. Coarse loamy soils were the most responsive to increasing management intensity. At age four, tree heights were greatest in the optimal group (4.63 m), followed by the intensive (4.31 m), and then the operational (3.06 m). Organic soils do not appear to respond to maximum management intensity. Predictability of SI25 was high especially starting at age four, with R² values ranging from 0.27 for the age four intensive group to 0.78 for the age four operational group. The optimal group had the greatest slope with an expected increase of 2.61, 2.75, 1.88, and 1.78 m in site index per additional meter of height at ages two, three, four, or five, respectively. Data from six different study sites indicate, the tallest (class one) and smallest (class five) trees changed percentile class the least often over time. As early as age two, over 40 % of observations in classes one and five had zero changes in class through age 13. Young tree data were effective in predicting SI25, and height dominance appeared generally set early in the rotation.

我们评估了五龄或五龄以下小叶松（Pinus taeda L.）的三个目标：1）不同土壤类型和造林强度对高度生长的影响；2）使用一至五龄高度预测基龄 25 地块指数（SI25）的准确性；3）轮伐初期表现出的高度优势是否会在整个轮伐期间保持。研究使用了美国东南部 42 个地点的数据，这些地点的土壤质地和管理强度（最佳、密集和操作）各不相同。管理强度和土壤对树高的影响很大。粗壤土对管理强度的增加反应最大。四龄时，最优组的树高最高（4.63 米），其次是强化组（4.31 米），然后是操作组（3.06 米）。有机土壤似乎对最大管理强度没有反应。SI25 的可预测性很高，尤其是从四龄开始，四龄密集组的 R2 值为 0.27，四龄操作组的 R2 值为 0.78。最佳组的坡度最大，在二龄、三龄、四龄或五龄时，每增加一米高度，场地指数预计将分别增加 2.61 米、2.75 米、1.88 米和 1.78 米。来自六个不同研究地点的数据表明，随着时间的推移，最高（一级）和最小（五级）的树木改变百分位数等级的频率最低。早在两岁时，超过 40% 的一等和五等观测值在 13 岁时等级变化为零。幼树数据可有效预测 SI25，而高度优势似乎在轮伐初期就已形成。

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引用次数: 0

Modeling regional forest site productivity accounting spatial structure in climatic and edaphic variables 区域林地生产力建模：气候和土壤变量的空间结构核算

IF 3.7 2区农林科学 Q1 FORESTRY

Forest Ecology and Management

Pub Date : 2024-11-01 DOI: 10.1016/j.foreco.2024.122360

Mukti Ram Subedi , Andres Alejandro Baeza-Castro , Puneet Dwivedi , Bridgett Costanzo , James A. Martin

With increasing interest in sustaining productivity amid changing climate, disturbance regimes, and management practices, an accurate forest productivity estimate is important to develop sustainable management regimes. Our goal was to estimate and map the potential productivity of co-occurring tree species. We used forest inventory and analysis (FIA) data and climatic and edaphic variables to model the composite site index (CSI) as a proxy of potential forest productivity. Initially, we identified the site index model for selected species: slash pine (Pinus elliottii), longleaf pine (Pinus palustris), loblolly pine (Pinus taeda), and yellow poplar (Liriodendron tulipifera). We then standardized species-specific site index (SI) values to generate composite site index (CSI) values. Finally, we used a random forest (RF) machine learning algorithm (ML) to predict CSI values based on climatic and edaphic factors while addressing spatial dependencies in the data set. The RF model explained 81 % of the variation (R²_adj = 0.81), with a mean bias of 0.11 m and a mean absolute error (MAE) of 3.37 m. The accuracy of modeling and mapping forest productivity using CSI depends on the quality and spatial distribution of national forest inventory data at the species level and climatic information. We recommend modeling forest productivity that accounts for spatial structure in the data to reduce overinflation of overall accuracy.

随着人们对在不断变化的气候、干扰机制和管理实践中维持生产力的兴趣与日俱增，准确估算森林生产力对于制定可持续管理机制非常重要。我们的目标是估算和绘制共生树种的潜在生产力。我们利用森林资源清查和分析（FIA）数据以及气候和土壤变量，建立了综合地点指数（CSI）模型，作为潜在森林生产力的替代指标。首先，我们确定了选定树种的地点指数模型：斜纹松（Pinus elliottii）、长叶松（Pinus palustris）、龙柏（Pinus taeda）和黄杨（Liriodendron tulipifera）。然后，我们将特定物种的地点指数 (SI) 值标准化，生成综合地点指数 (CSI) 值。最后，我们使用随机森林（RF）机器学习算法（ML）来预测基于气候和土壤因素的 CSI 值，同时解决数据集中的空间依赖性问题。RF 模型解释了 81% 的变化（R2adj = 0.81），平均偏差为 0.11 米，平均绝对误差 (MAE) 为 3.37 米。利用 CSI 对森林生产力进行建模和绘图的准确性取决于国家森林资源清查数据在物种层面的质量和空间分布以及气候信息。我们建议在建立森林生产力模型时考虑数据的空间结构，以减少总体精度的过度膨胀。

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引用次数: 0