First Results of Monitoring the New Invasive Species Prunus serotina Ehrh. Population inside the Regeneration Area of Common Oak-Hornbeam Forest in Western Croatia

Black cherry ( Prunus serotina Ehrh., Rosaceae) is a widespread invader of the European temperate forests and a significant component of the human-caused part of the global environmental changes. Its successful invasion results from a complex interaction between the species life traits and the recipient ecosystem attributes. While it has been recorded to develop spontaneously in numerous European countries, in Croatia information details on its population distribution, as well as its current status, are still missing. The individuals of P. serotina were found in the pedunculate oak (Quercus robur L.) forest regeneration area of Jastrebarsko forest management unit in 2018. This alerted us to start to monitor its spreading area, status and impact on the native plant species in a four-year period (2018-2021). In order to investigate the habitat characteristics, phytosociological approach was applied. In addition, the area was surveyed using an unmanned aerial vehicle (UAV) DJI Mavic 2 Pro and DJI Ground Station Pro. The results showed that P. serotina spread considerably in the regeneration area, which indicates its invasive character. It also caused alteration in current vegetation. Fast initial expansion of P. serotina in 2019 was slowed down in the next 2 years due to performed tending activities, suggesting mechanical measures could help to control its invasive spreading at an early stage of development. This research brought up the first record of the Prunus serotina species in pedunculate oak forest regeneration area of western Croatia with a recommendation to continue the monitoring survey in order to help prevent its spread in the future.

How Can Remote Sensing Reduce Required Human Intervention in Robotic Forest Regeneration

In this article, we introduce an alternative solution for forest regeneration based on unmanned ground vehicles (UGV) and describe requirements for external data, which could significantly increase the level of automation. Over the past few decades, the global forested area has decreased, and there is a great need to restore and regenerate forests. Challenges such as the lack of labor and high costs demand innovative approaches for forest regeneration. Mechanization has shown satisfactory results in terms of time-efficient planting, although its usage is limited by high operational costs. Innovative technologies must be cost-efficient and profitable for large scale usage. Automation could make mechanized forest regeneration feasible. Forest regeneration operations can be automated using a purpose built unmanned platform. We developed a concept to automate forest planting operations based on mobility platform. The system requires external data for efficient mobility in clear-cut areas. We developed requirements for external data, analyzed available solutions, and experimented with the most promising option, the SfM (structure from motion) technique. Earth observation data are useful in the planning phase. A DEM (digital terrain model) for UGV planter operations can be constructed using ALS (airborne laser scanning), although it may be restricted by the cost. Low-altitude flights by drones equipped with digital cameras or lightweight laser scanners provided a usable model of the terrain. This model was precise (3–20 cm) enough for manually planning of the trajectory for the planting operation. This technique fulfilled the system requirements, although it requires further development and will have to be automated for operational use.

Fauna biodiversity as one of Repong Damar forest health indicators

Repong Damar Pekon Pahmungan has a diverse fauna, especially primates. Primates have great benefits for forest sustainability, because the fruit seeds ingested by primates will help spread biodiversity and forest regeneration. The presence of primates can also be an indicator of forest health. The health condition of the repong damar forest is very influential on its sustainability so that one of the health indicators that can be used is biodiversity. Biodiversity of fauna can be identified by using the FHM (Forest Health Monitoring) method to determine the diversity and condition of its health status. Repong Damar has a diversity of primate fauna, namely long-tailed monkeys and gibbons found in cluster plots 3 and 5. Based on this, Repong Damar Pekon Pahmungan has poor forest health status.

The views of forestry employees on the cultivation of food crops in forest areas: a case study in Central Java

The environment and forestry sectors are expected to contribute to achieving food sovereignty. However, the cultivation of food crops in forest areas for commercial purposes is still limited since incommodity nomenclature, the food cropsareonly as crops. The objective of this study was to find out the views of forestry employees in Central Java on the cultivation of food crops in forest areas. Data was collected through a survey and analyzed through a descriptive quantitative method. The results showed the views of forestry employees were as follows. First, food crops need to be cultivated in forest areas on a large scale to increase forest benefits for communities and companies. Food crops such as paddy and maize were cultivated using an intercropping system during forest regeneration, shade-resistant food crops such as coffee and porang were cultivated under forest stands and fruit crops such as durian and mangosteen were cultivated in a mixture with woody trees. Second, foods obtained from the forests were recorded in statistics of environment and forestry and accounted for as contributions of environment and forestry sector. Therefore, the forests need to be managed for wood and food production to support food sovereignty.