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Franco Freitas Quevedo

CMPC Research and Nursery Coordinator


The influence of seedling quality on forest productivity

The Brazilian forestry base is recognized for its progressive technological and innovative development, which makes our gardens a world reference in productivity. In this context, there is a continuous need for advances in the quality of operations in the sector so that the average productivity of forests remains as a reference standard.

These factors are directly related to the production of high quality seedlings, since they reduce planting heterogeneity, positively impacting management, the survival of seedlings in the field and forest yield. For a forest to have an above-average yield, it is equally important that the basis of the production process is well conducted, which will result in the formation of seedlings with adequate quality parameters for planting.

For this, the entire propagation process must be monitored and audited, from fertilization and the conduction of the strains in a clonal mini-garden to their shipment. The survival, establishment and initial start of the cultural treatment are essential for the success of the planting, and these factors are directly linked to the quality of the seedlings shipped from the nursery.

The quality of the seedlings needs to be audited, as this is essential for the good development and formation of the forest. Based on analyzes and experimental results, together with the expertise of nurserymen, some parameters for selecting a good quality seedling must be observed and considered as evaluation criteria. The most evaluated parameters should be:

• Height: The seedlings should be between 20 centimeters and 40 centimeters. A minimum distance between the leaves and the ground is necessary so that, in winter, the seedlings freeze and, in summer, the collar burns.
• Age: For seedlings older than 130 days, shipping must be restricted. “Old” seedlings have a smaller number of active roots, difficulty in starting up in the field and a lower survival rate.
• Leaves: Three or more pairs of leaves. A plant with less than 3 pairs of expanded leaves cannot carry out photosynthesis completely and correctly, thus causing a decrease or delay in its full development.
• Stem pattern: Bifurcated seedlings or those with an inclination greater than 45 degrees should be avoided.
• Toilet: Many branches in a seedling or branches that are already very lignified must be cleaned.
• Leaf Spots: All leaf spots caused by disease must be recovered prior to shipment.
• Rustification: Red tips, reddish stem and mechanical resistance to bending.
• Health and nutrition: Absence of disease symptoms and nutritional imbalance.
• Root: Root system well formed and well distributed, with active roots and absence of air pockets.

A high quality seedling becomes a high standard forest. These studies, over the years, have been repeated, and the results always corroborate this premise. Seeking to reach the maximum development potential of the gardens, CMPC carries out a quality evaluation control of the seedlings in four levels:

1: EPS seedling production;
2: Quality inspection EPS;
3: CMPC nursery analyst;
4: Forestry EPS;

Quality assessments of seedlings for planting are carried out at the time of shipment. A sampling of all boxes is selected, analyzing the main quality parameters. After a careful analysis, a certificate is generated. To be classified, seedlings need to reach a minimum indicator of 80 points. Otherwise, they are not shipped. Over the past few years, different field experiments have been carried out to determine and validate the criteria for evaluating the quality of seedlings in the nursery.

In one of the experiments, the seedlings were segregated into three groups with different quality standards, the groups being:

A: the best quality seedlings were selected;
B: seedlings of intermediate quality; and group
C: lower quality seedlings. The evaluation of the parameters and their influence on the quality of the forest were observed. In analysis, pattern A seedlings resulted in a more productive forest with high survival, as shown in the table below.

The results show the gains obtained with a high quality expedition, in which a pattern A seedling, at 24 months, is 7 percentage points higher than pattern C seedlings. The quality of the seedlings associated with the correct implantation management are the success factors in forest productivity. 

Currently, the quality controls carried out are based on sampling, as the volumes of seedlings shipped daily are high.

Therefore, the search for an automatic seedling evaluation system based on already parameterized data would optimize the evaluation process, resulting in an increase in the number of seedlings analyzed and in a more realistic evaluation of each load, with a much greater accuracy than that you have today.

One of our purposes at CMPC is the continuous search for modernization, innovation and mechanization of activities, with the analysis of the quality of seedlings shipped being one of the focuses of the work. We are evolving together with technology companies in the development of this equipment for technological advancement in the inspection of seedlings. Quality control of seedlings should be treated as an investment, considering that measuring the quality of all operations, including seedlings, generates gains, increases productivity and produces better forests.