The complex of machines for low-cost artificial reforestation in the taiga zone

Problems of mechanization of artificial reforestation in the taiga zone are increasing the productivity of manual labour and reducing the costs of subsequent young stand treatment (early tending and early pre-commercial thinning). Petrozavodsk State University has developed the complex of machines and technologies capable to solve these problems. This complex includes: seeder, root-cutter, dynamic hole-maker and mechanical mounder. Seeder and root-cutter are intended for growing enlarged seedlings with an open root system in forest nurseries. Seeder provides mechanization of sowing seeds. Root-cutter is used for pruning the root systems of seedlings during cultivation. Dynamic hole-maker provides strip soil clearing, surface tillage and preparation of holes for manual planting of seedlings. The hole-maker is also capable to make soil scarification and sowing forest seeds. Mechanical mounder provides strip clearing in the forest plot and creation of humus mounds with mineral soil cover for manual planting of seedlings. Basic technological parameters of the complex of machines have been also substantiated at the Petrozavodsk State University.

Demography and productivity during the recovery time sequence of a wild edible bamboo after large-scale anthropogenic disturbance

Anthropogenic disturbances in forest management practices can affect wild edible plants. Soil scarification is a large-scale disturbance that may cause long-term reduction in productivity of edible dwarf bamboo, Sasa kurilensis, in northern Japan. For their effective and sustainable use, we need to understand the recovery process after such disturbances. At 14 study sites in the Teshio Experimental Forest of Hokkaido University where soil scarification had been conducted between 2 and 44 years prior, the number and stem diameter of old and young (newly emerged, edible) culms was recorded. At sites that were within 11 years of soil scarification, the proportion of old culms (<11%) was lower than in the control area where soil scarification had never been conducted. At sites where more than 15 years had passed since soil scarification, the relative number of old culms was nearly equal to that in control area. Additionally, the number of young culms increased with an increasing number of old culms. These results suggest that recovery of productivity (in term of number) of edible culms may take a few decades. In contrast, the culm diameter of young culms increased linearly with time since soil scarification, but the 95% confidence interval in this relationship suggests that dwarf bamboo can produce thick edible culms soon after soil scarification. These findings will provide useful insights into how to obtain high quality bamboo culms following anthropogenic disturbances in future.

Forest fire survival in young, dense Betula ermanii stands on soil scarification sites

A forest fire in a cool-temperate broad-leaved forest in northern Japan, from 26 May to 19 June 2019, provided an opportunity to examine its effects on young and dense birch (Betula ermanii Cham.) stands in soil scarification sites. To characterise post-fire responses (survival and resprouting) of birch, we set up two plots, 6 months post fire. We investigated trunk diameter at breast height and burn marks on tree trunks (scorch height and charring percentage around the tree bole) of all B. ermanii trees in both plots. Survival and resprouting of each tree were monitored over 2 years (6 and 16 months post fire). To quantify post-fire vegetation recovery in the forest floor, we manually mapped the dominant understory plant, dwarf bamboo (i.e. Sasa kurilensis (Rupr.) Makino et Shibata), from orthomosaic images obtained by an unmanned aircraft vehicle, and estimated the recovery rate in the second year post fire. Additionally, seedlings of woody species were counted in both plots. Size-dependent survival rates of plants in both plots were similar in the first year post fire. All B. ermanii trees died without resprouting in the second year post fire, indicating the lethal effects of fire on young birch trees. Moreover, a high recovery rate of dwarf bamboos over 2 years in both plots and limited seedling establishment of woody plants suggest that the fire resulted in regeneration failure of young stands in the scarification sites. On the basis of these findings, we propose future management of stands in soil scarification sites post fire, considering the vulnerability of young trees and the rapid change in vegetation from young forest to dense birch cover post fire.

Slash Pile Burn Scar Restoration: Tradeoffs between Abundance of Non-Native and Native Species

The accumulation of live and dead trees and other vegetation in forests across the western United States is producing larger and more severe wildfires. To decrease wildfire severity and increase forest resilience, foresters regularly remove excess fuel by burning woody material in piles. This common practice could also cause persistent ecosystem changes such as the alteration of soil physical and chemical properties due to extreme soil heating, which can favor invasion by non-native plant species. The abundance and species richness of native plant communities may also remain depressed for many years after burning has removed vegetation and diminished propagules in the soil. This adds to the vulnerability of burned areas to the colonization and dominance by invasive species. Research into the use of revegetation techniques following pile burning to suppress invasion is limited. Studies conducted in various woodland types that investigated revegetation of pile burn scars have met with varying success. To assess the effectiveness of restoring pile burn scars in Rocky Mountain National Park, Colorado, we monitored vegetation in 26 scars, each about 5 m in diameter, the growing season after burning. Later that summer, we selected 14 scars for restoration that included soil scarification, seed addition, and pine duff mulch cover. We monitored the scars for four years, pre-restoration, and three years post-restoration and found that the cover of seeded species exceeded the surrounding unburned areas and unseeded controls. The restoration seeding suppressed cover of non-native species as well as native species that were not seeded during restoration. Our results suggest that restoration of pile burn scars could be a useful tool to retard the establishment of invasive plant species when there are pre-existing infestations near scars. However, this must be weighed against the simultaneous suppression of native species recruitment. Monitoring for periods more than three years will help us understand how long the suppression of native and non-native species by restoration species may persist.

Effects of Skidding Operations after Tree Harvesting and Soil Scarification by Felled Trees on Initial Seedling Emergence of Spanish Black Pine (Pinus nigra Arn. ssp. salzmannii)

Skidding operations are thought to have negative impacts on soil emergence because they may increase soil compaction and reduce vegetation cover and the soil’s organic matter content. We investigated whether and to what extent tree harvesting and subsequent skidding initially altered seedling emergence in two Mediterranean forests of Pinus nigra Arn. ssp. salzmannii (Spanish black pine) in the Cuenca Mountains (Spain). Our main objective was to compare the Spanish black pine seedling emergence rate among skid trails, soil areas scarified by felled trees, and areas undisturbed next to harvest operations. In addition, we selected an unmanaged stand as reference, in order to look for evidence of seedling emergence under natural conditions. We measured Spanish black pine seed fall and seedling emergence immediately after harvest operations in two locations in the Cuenca Mountains (Palancares and Majadas forests), which are typical forests in Cuenca Mountains. The results showed that the Palancares site presented higher seed fall in comparison to the Majadas site. In addition, seed fall was higher in the unmanaged stand, as we recorded a higher tree density in this site in comparison to harvested stands (Palancares and Majadas). Furthermore, our results demonstrated differences in seedling emergence between lower elevation drier Palancares and higher elevation wetter Majadas and relative differences in seedling emergence among skid trail, scarified, and undisturbed harvested areas. Finally, the unmanaged stand presented the highest seedling emergence in comparison to scarified, compacted, and non-disturbed harvested areas. Overall, the results suggest a short-term impact of skidding on seedling emergence, which should be considered for future management guidelines of Spanish black pine in the Mediterranean climate.

Scarification in no-tillage: soil physics and plant development

No-tillage is conservationist soil management for agricultural production and it is based on soil cover by crop residues and restricted mobilization to the sowing line. However, its structure can be affected by the excessive compaction resulting from the traffic of machines. The objective of this study was to evaluate soil physical properties and crop performance in no-tillage with and without scarification, combined with different successions of plant species, in a Humic Cambisol. For this, the species of black oat, wheat and forage turnip were cultivated in winter, and later, corn and beans in summer. Soil samples were collected at the beginning and at the end of the experimental period, while evaluations of plant yield were carried out in the final stage of development. Soil scarification reduces relative density (RD) and soil resistance to penetration (RP) after preparation of soil, with effect restricted to the surface layer. Such effects persist for one year, however RD and RP increase over time, regardless of soil management. RP is more sensitive for evaluation of soil compaction and correlates positively with RD, with exponential adjustment. The aerial biomass of black oat, wheat and forage turnip was not affected by soil scarification, and crop yield of beans and corn showed to be more related to the previous cultivation than the scarification in no-tillage.

Interaction of chemical attributes of an Red Oxisol in the brazilian Savannah cultivated with soy under two management systems

Soil compaction and nutrient accumulation on the surface have been a major problem. Soil scarification can alter nutrient variability due to partial soil mobilization. This research aimed to evaluate by multivariate techniques the main chemical attributes of the soil that best relate to soybean yield and production components. The experiment was performed in a dystrophic Red Oxisol, in the agricultural year of 2015/16, in Savannah area located in the Selvíria County, MS, Brazil. The experiment consisted of two cultivated areas, one under no-tillage system (NTS) implemented 13 years ago and another in minimum cultivation system scarified (MCSS). Were evaluated: population of plants, first pod insertion height, plant height, the number of pods per plant, grain per plant, grain per pod, the weight of 100 grains, grain yield and soil chemical attributes. Soybean yield was higher in NTS when compared to MCSS scarified. The values of pH, calcium content, magnesium and phosphorus in the layer of 0-0.10 m, as well as the content of K in 0.10-0.20 m, are the attributes that most contributed to the increase of soybean productivity in NTS and MCSS.

Fatores determinantes para a construção do potencial produtivo da soja em terras baixas

The soybean is an alternative of diversification and financial return to the rice farmer. However, it presents difficulties of cultivation and low yield due to the physical characteristics of the soil. In this scenario, the objective of this work was to verify the influence of soil scarification, the genetic material used and the sowing date. Three soybean cultivars, with yield potential classified as “medium”, “high” and “very high”, were sown in a scarified and non-scarified area, in the dates november 7th and december 10th, year of 2018. The scarification opperation occurred on october 1st. Initial establishment varied according to cultivar, soil mechanism and sowing date. Soil scarification effect was verified up to 100 days after the operation. Within the construction of the yield potential, scarification accounted for 14.4 %, sowing date 12.5 % and genetic material 73.1 % of crop grain yield, in the “high” and “very high” potential materials.