Variations of yield and utilisation of bilberries (Vaccinium myrtillus L.) and cowberries (V. vitis-idaea L.) in Finland

Abstract

So far, only rough estimates for the utilisation rates of wild berries in Finland have been available. One reason for this is that there has been a lack of empirical-knowledge-based studies concerning total yields of wild berries and their yield variations. This study had three aims: 1) total bilberry and cowberry yields of an average crop year were calibrated for different (abundant and poor) crop years using the inventory data on wild berries collected by the Finnish Forest Research Institute (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008); 2) national utilisation rates of bilberries and cowberries were calculated for three different berry years 1997-1999; and 3) regional utilisation rates of these berry species were calculated for the year 1997. According to calculations, annual bilberry yields in Finland vary from 92 to 312 million kg. For cowberry, the range of variation in total berry yields is from 129 to 386 million kg. It was also found that approximately the same proportion of the total yield of bilberries (i.e. 5-6%) was collected between 1997 and 1999. Utilisation rates of cowberries were also quite constant varying from approximately 8% to nearly 10%. In 1997, bilberries and cowberries were utilised most intensively in the eastern parts of the country and in the Oulu-Kainuu region. The results of this present study describe the situation before the phenomenon of foreign pickers. It can be presumed that commercial wild berry picking by migrant collectors has so far affected both national and regional utilisation rates of wild berries.

Modelling the coverage and annual variation in bilberry yield in Finland

“…This study represents a continuation of work by Miina et al (2009) and Turtiainen et al (2011). Our model of bilberry coverage (Model 1) considered a wider range of sites, including other sites where bilberry occurs in the field layer (categories b-g) as well as the mineral soil forests (category a) considered by Miina et al (2009).…”

“…Data were not available for all sample plots for every year and observations from a given year were cross-correlated due to annual variation in conditions. Thirdly, Turtiainen et al (2011) andSalo (2015) calculated mean annual bilberry yields (kg ha -1 ) using the method described by Turtiainen et al (2011), which used average weights of ripe bilberries on different site fertilities. The weights were obtained from earlier studies by Kuchko (1988) and Ihalainen et al (2003).…”

“…The indices obtained in this study were compared with berry yield indices derived from the mean annual berry yields presented by Salo (2015). Salo (2015) calculated a series of mean annual bilberry yields for 1997-2013 using MASI data and the method described by Turtiainen et al (2011). For the purpose of comparison we also scaled Salo's (2015) mean annual berry yields to have a mean of 100.…”

“…frost, pollination success and variation in precipitation and temperature (Raatikainen 1993;Wallenius 1999). Turtiainen et al (2011) calibrated the total bilberry yield in an average crop year for different crop years using the inventory data on wild berries (referred to as MASI data; Salo 1999) which was collected from permanent berry sample plots in [1997][1998][1999][2000][2001][2002][2003][2004][2005][2006][2007][2008]. The calibration was a two-stage process.…”

“…total berry yield during an average crop year). Turtiainen et al (2011) thus calculated that total annual bilberry yields in Finland would vary between approximately 90 and 310 million kg.…”