Storm Damages in "Pinar de Valsaín" forest: historic data and
problems coming from January 1996 storm.
ABSTRACT CONCERNING : Common practice
TYPE OF DOCUMENT : Technical publication
THEME : Harvesting operations 7; Economic aspects
TITLE ABSTRACT : Storm Damages in "Pinar de Valsaín" forest: historic data and problems comimg from
january 1996 storm.
ORIGINAL TITLE : Daños por temporales en el monte "Pinar de Valsaín". Datos históricos y problemas
generados por el temporal de enero de 1996
AUTHORS : Javier DONÉS y Montserrat GARRIDO
PUBLICATION DATE: 2001
ORGANISATION : Public Forest Organism "Centro de Montes de Valsaín" and Public Forest Enterprise
REFERENCE ABSTRACT: Proceedings of the 3rd National Forest Congress "Sierra Nevada 2001" (Granada,
Spain). Vol. V, pag. 315-320. Ed. Junta de Andalucía-Tragsa-Sociedad Española de Ciencias Forestales.
This communication comments the series of repeated storm damages in this emblematic Spanish public Scots
pine natural forest, located in a mountain region of Central Spain. Main interest is devoted to the recent 1996
storm, from wich data on affected surfaces, volume obtained and harvesting costs are presented.
Regarding historic series of storm damages, many references from XVIIth century to 1940 are registered, but the
complete data set about number of stem and volume affected are presented from 1940 to present. The most
important damages came from 1959/60, 1974/75, 1980/81 and 1995/96 storm (Figure 1 and Tables 1 and 2).
Figure I: Number of trees (less dark columns) and volume (darker columns) series of wind damages at Valsaín
TABLE Nº 1. VOLUME AND NUMBER OF EXTRACTED TREES (FROM THE 1966 STORM) EACH
AÑO NUMBER OF VOLUME M
TREES (Ø >
3 UB NUMBER OF
SMALL TREES (10
TO 30 CM)
1996 39.849 29.619 54.433
1997 9.666 5.753 33.027
1998 7.976 2.939 49.257
1999 4.538 1.567 17.887
2000 44.235 6.216 5.193
TOTAL 106.264 46.094 159.797
TABLE Nº 2. PINES WITH DIAMETER LESS THAN 30 CM FROM DAMAGES CAUSED BY JANUARY
1996 STORM. RESULTS OF AUCTION SELLINGS
1997 1998 1999 2000 TOTAL
4.584,1 3.066,4 3.464,8 2.723,0 3.023,3 16.861,5 t
75.832,60 49.869,70 56.349,50 44.285,50 42.288,30 268.625,70 €
The last 1996 storm was those from which more volume was extracted, totalling (up to 2000) more than 46000
cubic metres from more than 260000 stems with diameter greater than 10 cm (106000 of them with diameter
greater than 20 cm, see Table 1).
Damages were spread over 6600 ha, more than 80 per cent of forest total surface. Main difficulties were found in
young even stands very strongly damaged (950 ha with average costs between 1800 and 2520 €/ha)
Total harvesting cost have been some 3 million € from 1996 to 2000.
Harvesting methods were manual (chainsaw) and skidding was performed by mules and horses combined with
winch skidders and forwarders. Besides, a big construction crane was employed to winch-skid timber in steep
The obtained timber was sawn in the public sawmill that exists besides the "Pinar de Valsaín" forest, except
almost 17000 tonnes of trees smaller than 30 cm that were sold at public auctions. An amount of some more than
265000 € was obtained in the cited 5-year period by this way (see Table 2).
Sanitary problems were not so great than expected. Piles were sprayed with synthetic pyretrines at landing
Young regeneration areas have been affected by Tomicus scolytus, but damages have not been very severe.
Damages caused by Ips scolytus and Diprion pini butterfly were detected but they were not so severe than
expected. Ips was treated using dead stems as tramps, which were treated afterwards.
Management derived implications are also commented: thinned stands are less affected than unthinned. Very
strong extractions are not recommended while leaving trees with well-shaped crowns and good h/d ratio is
necessary to avoid severe damages. Besides, the manager must planify the cuttings beginning from the opposite
side to the prevailing winds.