(1) Woody plant species selection for urban forests is one of the key factors in reducing traffic noise in urban areas, and the ability of sound wave attenuation by leaves is one of the foundations for species selection. However, less references regarding the relationships between leaf morphological traits and noise reduction have been reported, especially the relationships between leaf texture (LT), leaf surface roughness (LSR), and noise reduction. (2) Eighteen arbors and shrubs were selected based on leaf texture and surface roughness characteristics, and noise reduction was measured using white noise sources in a self-designed device in a quiet laboratory at night. Then, the changes in noise reduction with LT and LSR were analyzed. (3) The noise reduction was significantly affected by LT, LSR, and their interaction (p < 0.05). The coriaceous leaf was usually more efficient in noise reduction than the chartaceous leaf, and LSR had an auxiliary effect on noise reduction. The effects of noise reduction were mainly influenced by leaf texture through physical blocking and by leaf surface roughness through interference. (4) The findings demonstrate that leaf texture and leaf surface roughness are the suitable predictors for selecting highly efficient woody plants for establishing and improving noise-reduction-oriented forests.

Neighborhood competition plays a crucial role in the development of phenotypic traits and adaptive strategies within ecological systems. However, the specific mechanisms by which neighborhood competition influences the relationship between urban tree morphological traits and landscape quality remain poorly understood. This study focuses on urban green spaces in Beijing, aiming to elucidate the effects of neighborhood competition on both the morphological traits of individual trees and overall landscape quality. Additionally, it explores the interaction between neighborhood competition and landscape quality in shaping tree morphological traits. A field survey was conducted within the Sixth Ring Road of Beijing, establishing 180 landscape plots. Nine visual morphological traits of trees were assessed, and four morphological indices were constructed through factor analysis: the space occupancy index, canopy uniformity index, canopy expansion index, and trunk-crown inclination index. Moreover, through the implementation of questionnaire-based surveys, the Visual Aesthetic Quality (VAQ) was quantitatively analyzed to elucidate the relationship between individual tree morphology and landscape quality. The results reveal that neighborhood competition significantly influences tree morphological traits. As competition grades increases, the space occupancy index, canopy uniformity index, and canopy expansion index decrease significantly, whereas the trunk-crown inclination index shows a marked upward trend. Additionally, the response of tree morphology to neighborhood competition is more sensitive in medium and small diameter trees. The study also finds that the impact of neighborhood competition on tree morphological traits varies significantly across different levels of landscape quality. Furthermore, based on the analysis using Kriging interpolation, it was observed that there is a north-south gradient in both the Competition Index (CI) and VAQ. By investigating the relationships among these three factors, this research provides scientific insights for optimizing urban green space species composition and enhancing landscape ecological functions.

[目的]以气候变暖为主的气候变化对树木健康及生态系统的稳定产生了深刻影响.本文通过研究气候变化对远郊油松天然林和近郊油松人工林径向生长的影响,揭示城市远郊自然生态系统和近郊山地树木径向生长对气候敏感度的差别.[方法]建立了远郊和近郊油松林的标准年表及差值年表,分别与气候指标进行相关分析;利用R软件建立年轮指数与气候指标的最优模型;通过4个韧性力指标分析近郊油松径向生长对干旱条件的响应.[结果](1)两地均呈现气候暖干化现象,其中近郊地区气候暖干化现象更为严重.(2)年表中统计参数均显示,近郊油松径向生长对气候信息更敏感.(3)远郊油松径向生长与当年及上年秋冬季最低温、上年夏秋季标准化降水蒸散指数(SPEI)呈显著正相关;近郊油松径向生长与上年及当年夏季极高温呈显著负相关,与上年及当年夏秋两季的SPEI呈显著正相关;近郊油松径向生长与当年帕尔默干旱指数(PDSI)年均值呈显著正相关,且严重干旱事件期间对PDSI变化更敏感.[结论]远郊油松天然林和近郊油松人工林树木径向生长均存在"滞后效应",近郊油松林的树木径向生长受城市化的影响,对极端气候的响应更加敏感,更易受到夏季高温和干旱胁迫的影响;但是,在不超过承受阈值的前提下,近郊油松人工林树木径向生长可从长期干旱事件中恢复.

[目的]合理的林分密度是风景林经营的关键,为了提升风景林景观质量,应首先确定合理的经营密度.[方法]以北京市西山人工油松Pinus tabulaeformis风景林为研究对象,基于61块20 m×30 m标准样地的林分调查数据,结合空间竞争和树冠半径生长模型研究树冠生长规律并确定油松风景林的合理经营密度.[结果]1)从10个常用竞争指数中确定了相对树冠表面积RCS为最优竞争指数,决定系数最大(R2=0.6506,P<0.01),剩余标准差最小(Sy·x=0.6142,P<0.01);2)经检验,以RCS为修正参数的树冠半径生长模型预测值与实测值之间最大平均误差为-0.53,最大绝对标准误差0.57,潜在树冠半径的预估精度94.53％,单木树冠半径的预估精度为89.03％,能够有效地预测树冠半径生长;3)基于此模型,建立了不同竞争强度、不同立地条件、不同年龄的经营密度表.[结论]树冠对林分密度和空间竞争的敏感性很强,相同立地条件和年龄的林分中,林分密度越大,空间竞争越激烈,树冠生长受到影响越大.基于树冠半径生长模型建立的林分经营密度表,可以直观地展现不同竞争强度的油松人工林在各年龄阶段的树冠半径和适宜的林分密度.风景林经营实践中应按照不同培养目标选择合适的林分密度和竞争强度.开发封闭式观赏景观,宜选择竞争指数为0.8～0.9的中高密度林分;培育观赏型林内景观时,宜选择竞争指数为1.0～1.1时的林分密度;培育观赏型林内景观和开放式林下休闲空间,应控制竞争指数应大于等于1.2.

Abstract Background How to quickly predict and evaluate urban dust deposition is the key to the control of urban atmospheric environment. Here, we focus on changes of plant reflectance and plant functional traits due to dust deposition, and develop a prediction model of dust deposition based on these traits. Results The results showed that (1) The average dust deposition per unit area of Ligustrum quihoui leaves was significantly different among urban environments (street (18.1001 g/m2), community (14.5597 g/m2) and park (9.7661 g/m2)). Among different urban environments, leaf reflectance curves tends to be consistent, but there were significant differences in leaf reflectance values (park (0.052–0.585) > community (0.028–0.477) > street (0.025–0.203)). (2) There were five major reflection peaks and five major absorption valleys. (3) The spectral reflectances before and after dust removal were significantly different (clean leaves > dust-stagnant leaves). 695 ~ 1400 nm was the sensitive range of spectral response. (4) Dust deposition has significant influence on slope and position of red edge. Red edge slope was park > community > street. After dust deposition, the red edge position has obviously “blue shift”. The moving distance of the red edge position increases with the increase of dust deposition. The forecast model of dust deposition amount established by simple ratio index (y = 2.517x + 0.381, R 2 = 0.787, RMSE (root-mean-square error) = 0.187. In the model, y refers to dust retention, x refers to simple ratio index.) has an average accuracy of 99.98%. (5) With the increase of dust deposition, the specific leaf area and chlorophyll content index decreased gradually. The leaf dry matter content, leaf tissue density and leaf thickness increased gradually. Conclusion In the dust-polluted environment, L. quihoui generally presents a combination of characters with lower specific leaf area, chlorophyll content index, and higher leaf dry matter content, leaf tissue density and leaf thickness. Leaf reflectance spectroscopy and functional traits have been proved to be effective in evaluating the changes of urban dust deposition.

分析干瘠立地中不同树种根功能性状的变化及差异,研究不同树种对干瘠环境的适应对策。试验材料为林龄、林分密度相对一致的石质山区主要观赏树种（黄栌、山桃、栓皮栎）,采用挖掘法获取树木细根,测定细根形态参数。根据田间持水量和石砾含量分别设置4个干瘠梯度（轻度、中度、重度、极度）,对比分析北京干瘠地3种树种根功能性状,探讨干瘠立地中不同树种根系形态的差异及其对特殊生境的适应。结果表明:干旱、瘠薄均对树木的根功能性状产生影响,但对不同性状以及不同树种的影响程度具有差异,其中对山桃根系的影响最大;3种树种根功能性状在不同干瘠等级下存在显著变化,同一性状的变化因树种不同而异。从轻度到极度干旱,3种树种的RL均逐渐减小,但是黄栌变化不显著;黄栌、栓皮栎RTD随干瘠的加剧而减小,而山桃随干瘠的加剧而增加;黄栌和山桃SRL随干旱、瘠薄的加剧,表现出一致的规律,即从轻度到极度,其SRL随即减小,而栓皮栎SRL随干旱、瘠薄的加剧而增大;随干瘠的加剧,黄栌SRA显著减小,山桃、栓皮栎SRA随干瘠的加剧而增大。树木对干瘠环境的变化都有一定的响应能力及适应对策,能够通过自身的形态变化来适应不断变化的环境,但不同物种对干瘠环境变化的适应途径不同,通过权衡碳分配、碳消耗采取了相应的生态适应策略,不同树种间存在明显差异。本研究3种树种中,黄栌在干瘠环境下根系性状变化不显著,耐干瘠能力较强;干瘠胁迫对山桃根系性状影响显著,山桃通过主动调节根系形态变化来适应不断变化的环境,具有较强的抗干瘠能力;栓皮栎的细根数量多,吸收土壤水分、养分能力较强,能够在干瘠环境中快速生长。

Biogenic volatile organic compound (BVOC) is an important part of forest healthcare effect, while it has not received enough attention in urban greenspace construction. Consequently, the aim of this study was to analyze BVOC emission rates and compositions released from leaves and flowers of landscape species in urban greenspace and to make suggestions for species selection and planting configuration in urban greenspace construction. BVOC emissions were collected and analyzed using dynamic flow enclosure technique with GC-MS in summer months (for leaf) and spring months (for flower) from 14 woody landscape species in northern China, which are 2 coniferous species (Pinus tabuliformis and Sabina vulgaris) and 12 broad-leaved species (Viburnum opulus, Kolkwitzia amabilis, Philadelphus pekinensis, Lonicera maackii, Cercis chinensis, Deutzia parviflora, Berberis thunbergia, Kerria japonica, Rosa xanthina, Syringa oblata, Syringa reticulata, and Cerasus serrulata). We found leaf emission rates of coniferous species were more than 20 μg∙g-1Dw∙h-1 and mainly consisted of monoterpenes, while that of sampled broad-leaved species were less than 10 μg∙g-1Dw∙h-1 and mainly consisted of fatty acid derivatives. Most broad-leaved species had relatively high emission rates of flowers, ranging from 15 to 115 μg∙g-1Dw∙h-1. Flower emissions of Syringa oblata and Syringa reticulata contained large amounts of aldehydes, and that of other broad-leaved species mainly contained terpenes, alcohols, and esters. We suggest the species with leaves that release large amounts of monoterpenes, and species with flowers that release large amounts of fragrant compounds are classified as healthcare species, while species with a dense crown and low emission rates of pungent compounds are classified as space-creation species. Based on this, planners could design urban greenspace with healthcare effects, and develop multi-functional, innovative, and sustainable urban greenspaces.

于2013-2016年7-8月,利用小气象站观测北京城市森林小气候特征,研究了城市森林冠层结构对人体舒适度的影响.结果表明:①叶面积指数(ILA)(r=-0.314,P=0.002),平均叶倾角(AMT)(r=0.472,P<0.001),冠层厚度(HCT)(r=0.458,P<0.001),冠下高(HCB)(r=0.692,P<0.001)和冠高比(RCT)(r=0.254,P=0.014)与林下舒适度(S)显著或极显著相关,其中平均叶倾角、 冠层厚度、 冠下高与林下舒适度相关性较高;叶面积指数(r=-0.356,P=0.001),冠高比(r=0.433,P<0.001)和冠层通透度(PC)(r=0.738,P<0.001)与舒适变化强度(dS)极显著相关,其中冠高比和冠层通透度与舒适变化强度的相关性较高.②利于提高舒适度的平均叶倾角、 冠层厚度和冠下高的取值区间分别为27.48°±1.67°,(7.40±0.09)m和(2.67±0.06)m;使林内舒适度优于林外的冠高比和冠层通透度取值区间分别为0.72±0.003和6.51％±0.884％.③平均叶倾角和冠下高的协同作用对林下舒适度的解释程度为51.1％;冠高比和冠层通透度的协同作用对舒适变化强度的解释程度为55.5％.林内舒适度受多个结构指标共同影响,单一指标无法准确预测林内舒适度,如何构建与林内舒适度拟合优度较高的综合结构指数还有待进一步研究.

构建表征大叶黄杨形态观赏性指数并研究不同生长抑制剂对大叶黄杨观赏指数的影响.在北京市鹫峰苗圃,将不同质量浓度的3种生长抑制剂(脱落酸ABA(A)、多效唑PP333(P)以及三碘苯甲酸TIBA(T))以L27(313)正交设计方案混合,并用其对密植成绿篱状的大叶黄杨扦插苗进行叶面喷施,选取10个灌木观赏性相关指标,采用因子分析法构建叶片光彩度指数、分枝度指数、叶形态指数及绿度指数4个观赏性指数,分析生长抑制剂对各观赏性指数的影响.结果表明:脱落酸对叶片光彩度、叶形态以及分枝度均有抑制作用,对叶绿度有促进作用,且较高质量浓度脱落酸对叶光彩度及形态的抑制作用较低,较低质量浓度脱落酸对分枝度的抑制作用较低;多效唑对叶形态有较好促进作用,较低质量浓度多效唑对分枝度及叶绿度的负面作用较低;三碘苯甲酸对光彩度、叶形态以及分枝度均有抑制作用,且抑制作用随三碘苯甲酸质量浓度增加而增强,低质量浓度三碘苯甲酸对三者观赏性的负效应较低,三碘苯甲酸对叶绿度有显著促进作用,且促进作用随三碘苯甲酸质量浓度增加而增强.脱落酸、多效唑、三碘苯甲酸以及三者交互作用通过影响叶片光彩度、分枝度、叶绿度及叶形态而影响大叶黄杨篱观赏性.

目的]探究抑制剂对大叶黄杨生长的抑制作用以及对其叶片形态和光合作用的影响,为灌木绿篱的化学修剪提供技术指导。[方法]在北京林业大学林场苗圃采用3种生长抑制剂(多效唑(PP 333 )、三碘苯甲酸（TIBA）以及脱落酸（ABA）)对密植成绿篱状的1年生大叶黄杨扦插苗进行叶面喷施,对其生长、叶片形态及光合作用等指标进行测定。[结果]3种抑制剂均有矮化植株、抑制新梢生长的作用,矮化效果最佳、抑制作用最强的为PP 333 ,且高浓度PP 333 对于高生长的抑制作用持效性较长。叶宽、叶厚以及叶面积在短期PP 333 处理下高于对照。PP 333 能提高大叶黄杨净光合速率,主要通过增加叶厚、气孔导度、叶肉导度及叶绿素含量来实现,并且PP 333 使蒸腾速率提高的同时降低了水分利用效率。TIBA有显著减小叶长、叶宽的作用,但能使叶厚增加,且随浓度的增加作用效果增强,主要通过减小叶面积,降低叶肉导度、气孔导度、胞间CO 2 浓度及叶绿素含量来降低净光合速率。ABA能增加叶面积(10 mg·L -1 处理除外)、叶长以及减小叶片厚度,通过抑制气孔导度、叶肉导度、叶绿素含量降低净光合速率。TI-BA及ABA均通过降低蒸腾速率,使水分利用效率提高。[结论]3种抑制剂均有矮化植株、抑制新梢生长的作用,并且影响叶片发育,进而影响叶片光合作用,且800 mg·L -1 的多效唑对大叶黄杨具有较好的正向作用。

Morphological plasticity is closely related to the ability of plant growth and resource utilization, which is an important manifestation of plant survival strategy in specific environment. To study the relationship between root morphological plasticity and ecological strategies of the plant is significant to understand the mechanism of plant adaptation to the environment. With 1-year-old Cotinus coggygria seedlings as the study materials, this paper applies the pot experiment in greenhouse and sets up five different levels of nutrient supply to analyze the root morphology characteristics ( root length, surface area, root tissue density, root fineness, root branching density, etc. ) and different diameters of root morphology ( root length, root surface area, root volume, root tips) to study the changes of morphological and functional plasticity in the plant seedlings. The results indicated that different levels of nutrient supply showed significant (P<0. 01) interaction on root length, surface area, root tips, root forks, root tissue density, average root diameter and root fineness of the plant seedlings. In the pure sand environment, the seedlings were most closely related to the root length, root surface area and root fineness. In the environment with limited nutrient restriction, the seedlings were mainly changed by root length, root surface area, root number and branch. However, the relationship between root tip density, root branch density, root diameter and root volume was most closely related in the relatively light and medium environment. In the whole soil environment, the seedlings were mainly affected by the change of root tissue density. To a certain extent, limited nutrient supply can stimulate ≤1. 0 mm diameter fine roots and limit > 1. 0 mm diameter fine roots. Morphological and functional plasticity in the plant seedlings reflected that the levels of nutrient supply significantly changed the strategies of nutrient absorption of Cotinus coggygria seedlings. From nutrient-sufficient to nutrient-limited and nutrient-deficient condition, seedlings tend to change their ecological strategies from enhancing the utilization ability in situ, enhancing the absorption ability in situ and expanding the absorption range, improving the storage and transportation ability, and finally change to the endurance strategies.

以林内景观斑块结构为基础,对北京市各类公园游憩型景观林景观斑块特征进行了分析.北京市各类公园游憩型景观林可分为中密度锻炼型景观林、中密度休闲型景观林、中高密度锻炼型景观林、高密度休闲型景观林、低密度综合景观林等5类.而具有低林分密度、高草本覆盖、适量灌木覆盖、丰富的色彩数量、乔草或乔灌草结构的林内景观更符合大众审美.在16个景观斑块要素中,景观密度越大,色彩斑块的SHDI越低,草本覆盖率越高PLADJ和AI越高、而NP、PD、景观斑块形状指数LSI越低.景观指数变化对林内景观美景度影响程度依次为SPLIT＞CONTAG＞PAF＞SIEI＞SHDI.随着美景度等级降低,CONTAG呈现线性递减趋势,而PAF、SPLIT、SHDI和SIEI呈现非线性变化趋势.高密度和整齐划一式的林木排列以及简单的林下植被在一定程度上简化了林内景观要素的复杂性,并不利于提高林内景观质量,适当增加树种丰富度,通过提高垂直层次数量和多样化的林下植被,使用提高林下植被近自然程度、采取规则式和非规则式树木排列方式相结合的多样化水平空间配置,将有益于提高林下植被斑块色彩多样性,并可有效地提高林内景观质量.