Forest Management and Tree Nursery Operations
Forestry and Silviculture Fundamentals
Silviculture involves the continued exploitation and management of forest resources for sustainable use.
Key Forestry Concepts
- Reforestation: The action of restocking or the process that allows the re-establishment of a forest in an area that previously had forest cover.
- Afforestation: The implantation of forests in land that has never had natural tree vegetation.
- Artificial Regeneration: The creation of artificial forests through human intervention, such as direct sowing or planting seedlings from a tree nursery.
Tree Nursery Establishment and Management
Nursery Site Selection
The chosen location should be as representative as possible of the climatic and soil conditions of the area intended for reforestation.
- Location: Often serves as a central distribution point for seedlings.
- Size or Surface Area: The final size depends on the maximum area intended for reforestation annually. Typical areas include:
- Seedbeds (Almacigueras): 60 m²
- Pricking Out / Transplant Beds (Repica): 3660 m²
- Total Area (including roads and construction): 4000 m²
- Soil Type: Should preferably be flat with a maximum slope of 2-3% to facilitate rainwater drainage. Soil texture should be rich in organic matter, with appropriate pH levels.
- Water Availability and Quality: It is crucial to have water available all year round.
Water Supply Methods
Water can be supplied through various methods:
- Perforated pipes
- Hose aspersion
- Ditches
Essential Equipment and Tools
A well-equipped nursery requires:
- Water tank for the greenhouse area
- Sheds for tools, seedbeds, seeds, fertilizers, and pesticides
- Plant area and bare-root transplant areas
- Perimeter fence
Labor Considerations
It is advantageous to locate a nursery near a population center to ensure a readily available labor force.
Soil Conditioning
Proper soil conditioning is essential to provide the required nutrients for healthy plant growth.
Types of Nurseries
- Temporary or Mobile Nurseries: Occupy the ground for a certain period, then are dismantled or relocated.
- Permanent or Fixed Nurseries: Require a careful study of the soil, site layout, and detailed planning for construction and installation.
Nursery Site Preparation
Once the site for the nursery is chosen, the initial ground preparation must proceed.
Nursery Design and Planning
This is an important stage in establishing the nursery. It typically has three main parts:
- Germination section
- Growing and development section
- Construction and infrastructure
Seedbed Management
Seedbeds for seed germination should receive sufficient sunlight, air, and water. Mycorrhization is another permanent practice that takes place in seedbeds to enhance plant growth.
Seed Production and Collection
Most forest species are propagated through seeds.
Parent Tree Selection Criteria
Select parent trees that are:
- Strong, healthy, and vigorous
- Dominant within the stand
- Have a small and compact crown
- Exhibit a naturally important form
Seed Collection
Fruits and seeds can be fleshy or contained within membranous sheaths. Examples of seed yields:
- 100 kg of Eucalyptus globulus fruits yield 2 kg of seeds.
- 100 kg of Eucalyptus tereticornis fruits yield 5 kg of seeds.
- 100 kg of Eucalyptus camaldulensis fruits yield 6 kg of seeds.
- 100 kg of Eucalyptus viminalis fruits yield 4 kg of seeds.
Seed Documentation
Collected seeds should be documented with:
- Registration number and date of collection
- Technical and common names of the species
- Altitude and origin of the parent trees
- Site characteristics (e.g., soil texture)
Seed Quality
Key indicators of seed quality include:
- pH
- Purity
- Viability
Sowing Techniques
Seeds can be sown:
- Broadcast (to boleo)
- In lines
Sowing is typically done in late winter or early spring in seedbeds.
Pricking Out (Repica)
This involves the transplantation of individual seedlings into individual containers.
Shade House (Umbracle)
A fixed structure whose height allows for comfortable movement and work, providing shade for young plants.
Nursery Plant Care
Regular care is essential to protect plants from diseases and pests.
Propagation Methods
- Direct Seeding: Involves sowing seeds directly into the final planting site, bypassing the need for a nursery seedbed.
- Clonal Propagation (Agamic): Certain forest species can be multiplied or propagated vegetatively (asexually) through methods like cuttings or tissue culture.
Packaging and Transport of Seedlings
Seedlings are exposed to significant losses if the transfer time to the field is prolonged or if packaging is inadequate.
Forest Plantation Establishment
Site Selection Criteria
Consider flat or semi-eroded terrain before making a planting decision.
Planting Systems
For transplantation, it is important to maintain a regular spacing of plants to ensure optimal growth and resource utilization.
Purpose of Forest Plantations
Forest plantations serve the purpose of restocking abandoned forest areas or reforesting deforested lands.
Advantages of Forest Plantations
Plantations ensure high production compared to any agricultural management, contributing to sustainable resource use.
Forestry Practices
Key practices include:
- Preserving soil fertility
- Careful species selection
- Site review and initial establishment
- Vegetative maintenance and ongoing management
Environmental Aspects to Consider
Important environmental factors include:
- Soil protection
- Nutrient availability and decomposition processes
- Existing climate conditions
Types of Plantations
- Industrial Plantations: Often intensive and subject to specific management regimes for timber or other products.
- Protection Plantations: Established primarily for environmental benefits, such as soil erosion control, water conservation, or biodiversity.