Assessment of How Natural Stand Structure for Narrow Endemic Cedrus brevifolia Henry Supports Silvicultural Treatments for Its Sustainable Management

Cedrus brevifolia Henry is a narrow endemic tree species of Cyprus flora. The objectives of this study are to develop silvicultural treatments for the conservation of the species formations based on the stand structure analysis of C. brevifolia natural forest and to present the characteristics of the first application of the treatments through silvicultural interventions. Six structural types were distinguished in C. brevifolia formations in the study area located in the state forest of Paphos. For each structural type, six circular plots of approximately 500 m2 were established. In each plot, various measurements and estimations were recorded. Then, silvicultural interventions were applied in the plots of the mixed C. brevifolia formations. In the formations of C. brevifolia a great number of trees grow in the understory. In the very productive and in the poorly productive sites C. brevifolia occurs only in pure formations. The basal area of C. brevifolia in pure formations ranges from 19.04 m2·ha-1 in poorly productive sites to 38.49 m2·ha-1 in fairly productive sites. Cedrus brevifolia is the most competitive species of the study area as a result of both shade tolerance and the wide range of its site sensitivity behavior. The climax of the study area are the pure stands of C. brevifolia having an understory of Quercus alnifolia Poech and a sparse occurrence of Pinus brutia Ten., mainly in moderately productive sites. Forest practice has to, as much as possible, unite species formations in order to create extensive areas of C. brevifolia formations.

Reply to the comment by Bailey et al. on “Long-term decline of sugar maple following forest harvest, Hubbard Brook Experimental Forest, New Hampshire”

Sugar maple decline in eastern North America is caused by a complex combination of factors, with soil nutrition being one of several important determinants. Given the complexity of sugar maple population dynamics and the geographic extent of the species, we support Bailey et al.’s (2019, Can. J. For. Res. 49(7), doi: 10.1139/cjfr-2018-0207 ) argument to interpret results from Cleavitt et al. (2018, Can. J. For. Res. 48(1): 23–31, doi: 10.1139/cjfr-2017-0233 ) with due caution. The experiment at Hubbard Brook Experimental Forest represents an atypical application of contemporary forest practice in the White Mountain National Forest; however, some comments in Bailey et al. (2019) missed the point; others inaccurately characterized our paper. Cleavitt et al.’s (2018) 30-year record of vegetation recovery following whole-tree harvest documented a worrisome inability of a sugar maple population that successfully established after harvest to maintain its position in the understory. This lack of persistence on base-poor soils such as those in the mid and upper elevations of Hubbard Brook Experimental Forest suggests that the successful recruitment of sugar maple is not guaranteed.

Application of Viewshed and Spatial Aesthetic Analyses to Forest Practices for Mountain Scenery Improvement in the Republic of Korea

Forest practices for mountainous areas can enhance the scenery value and function of forests. However, forest scenery management is rarely implemented except for conservation areas and public forests. In this study, we first used the viewshed analysis to extract visible and invisible zones from the surface areas of ordinary mountains in Korea, and then we used spatial aesthetic analysis to interpret the human-recognized characteristics on the visible zones of mountain scenery. Finally, based on the results of both analyses, reasonable guidelines for forest practice planning were proposed to improve the scenery of ordinary mountains. The result shows that the viewshed analysis made it possible to extract visible and invisible areas from the surface areas of ordinary mountains, and to determine the scale of zoning for forest practices to improve mountain scenery. In addition, using spatial aesthetic analysis, it was possible to explain the characteristics of mountain scenery according to distance and elevational differences between viewpoint and target, and to suggest a treatment target and direction for forest practices to improve the mountain scenery. This study is meaningful in that the viewshed and spatial aesthetic analyses were applied to evaluate the current scenery of ordinary mountains and to present guidelines for forest practice planning to promote their own scenery values.

Accuracy of smartphone applications in the field measurements of tree height

As tree height is one of the important variables measured in forestry, much effort is made to provide its fast, easy and accurate determination. We analysed precision of two widely available smartphone applications (Smart Measure and Measure Height) during the field measurements of tree height. The data was collected in three Scots pine stands in central Poland. We found negative systematic error of both tested applications regardless the distance of the measurement (15 or 20 m). RMSE values of the height estimates varied from 1.01 to 2.46 m depending on the application used and the distance of the measurement. Value of the calculated absolute and relative errors significantly (p < 0.015) positively depended on the actual height of the measured trees and was more diverse for higher trees. Smartphone applications seem to be promising measurement tool for tree height determination, however as for the time being they require improvement before wider introduction into the forest practice.

Opportunities for the application of linear program­ming in forest management planning

In situations where it is necessary to consider a variety of options when making decisions in forestry (and in general), with the choice influenced by hardly comparable criteria and a number of conflicting interests, a possible solution is to use multiple criteria methods. One of these methods, which can be applied in forestry, is mathematical programming (in particular, linear programming). Linear programming has a long tradition of being used in the U.S. and European forestry, whereas in the forestry of Serbia it still represents a theoretically and practically unknown tool. Therefore, in this paper we analyze the possibility of applying the methods of linear programming in developing a plan of regeneration cutting in the poplar plantations of FMU "Topolik" managed by PE "Vojvodinasume." Using the aimed function (linear programming) and the corresponding software package the maximum yield that can be achieved by cutting the plantation was obtained. The planned management period was from 2012 to 2021 and its volume was 155 852 m3. The preset condition that the yield in half-periods remains equal was fulfilled (half-period I 77,925 m3, half-period II 77,927 m3). The maximum yield obtained with this methodology was by 4,040 m3 lower than the theoretically possible yield that would be obtained if all stands were cut down at the end of the second half-period, i.e. higher by 8,430 m3 than the yield that would be obtained if cutting of the stands were performed at the start of the management period. The results obtained and foreign experience in this area clearly indicate that linear programming can successfully be used to solve this problem and even more complex problems (than the one presented in this paper) in our local forest practice (multidimensional planning with a series of constraints).

Leaf area index of Norway spruce stands in relation to age and defoliation

This contribution presents LAI data of 17 Norway spruce stands of different age (from 15 to 102 years) and health status (defoliation ranging from 0 to 40 %) located in the Těšínské Beskydy Mts. (NE of the Czech Republic). Defoliation degree was estimated by ocular observation and LAI was estimated indirectly on the base of gap fraction method using LAI-2000 PCA (Li-Cor, USA). It was found that LAI decreased with stand age (approximately from 12.6 to 8.5) whereas defoliation increased. Therefore, strong relationship between defoliation and LAI as well as gap fractions was found. LAI appears valuable parameter for health status of stand evaluation due to linear relationship (r2 = 0.87) between LAI and defoliation. As LAI can be estimated more objectively by a canopy analyzer then the degree of canopy defoliation by ocular observation, there is a perspective for a wide use LAI in forest practice. The LAI values can be used for the evaluation of health status of Norway spruce stands.

The most invasive five woody plants control risks assessment: Strategic precondition for sustainable governance of natural resources in Serbia

Risks assessmentand management can play a key role in the reduction of damage caused by different types of forest pests, diseases and weeds in sustainable forestry practice development. Significant diversity of serious threats to forest ecosystems condition demands special governance instruments in a goal of increasing productivity while an environmental contamination and health hazard needs to be reduced to a minimum. Sustainable forest management can be better achieved through the preferment of appropriate assessment tools (with proper risk evaluation model developing and adapting it). During testing the increasing desire to apply the "precautionary principle" in the face of scientific uncertainty had been recognized. There's luck of scientific knowledge; studies are ongoing intensive but with decade or less delay of our country/ forest practice/ introduced plant influence research object existing results or their control usage background. Potentially serious consequences prejudgment leads to the driving force of a multidisciplinary approach in research process, with objective and invaluable field experience at the first place and guidance of it.

Effect of stand segmentation on growth and development of Norway spruce stands

Segmentation of stands by tracks is often the first phase of forest tending. However, a suitable track width is still discussed in forest practice in the Czech Republic. This article deals with the effect of track width on the growth characteristics of young spruce stands. Research involves several variants of European thinning experiment IUFRO CZ 14 Machov situated in Eastern Bohemia. Totally 3 variants were analyzed: 1 – non-segmented control plot without thinning and plots with forest tending (at top height 10 and 20 m) and with different present width of tracks (plot 3 – originally 3.5 m, plot 4 – originally 5.0 m). The significantly positive effect of stand segmentation and tracks on dbh and crown length was found only for individuals growing in the first row next to a track. As regards the stand volume and volume of mean stem, differences between variants with skidding track (3 and 4) were found minimal and insignificant. Therefore, the observation did not reveal any evident losses of production caused by different widths of skidding tracks.