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Learning from Mustila


Matthew Parratt is the Conifer Referee for the BSBI (Botanical Society of Britain and Ireland) and a research biologist at Forest Research. Together with Chloe Darling, who had made initial links with Finland, they went to Helsinki to start making arrangements for the 2020 RFS Overseas Study Tour. While there they visited Mustila Arboretum  - one of the destinations on the StudyTour - and this is Matt’s report on this fascinating part of their forests. 

Full details of RFS 2020 Overseas Study Tour to Finland from 30 August -10 September are available here. Bookings will open to Members and their partners on a first come basis.


For us here in the UK an arboretum is a collection of specimens, single examples carefully placed to show off their best features in a silvicultural trophy cabinet. Mustila takes a different approach. There are no extensive visitor centres, but instead a converted timber building where home baked food is served. No trace of immaculately trimmed grass paths, or gaudy information panels here; what you get instead is something that feels altogether less tamed, wilder, and more subtle. After exploring on our own for a few hours we were lucky enough to be shown around by Kimmo Kuusisto, the head gardener. His passion is evident, and he’s currently planting up some of the more open areas with more shrubs, perennials and bulbs, extending the season of interest. Here and there are some more hopeful experimental plantings including a few very unexpected cacti nestled in amongst the rocks below a canopy of Scots pine.

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 Matthew Parratt inspecting Pinus Peuce at Mustila 


Mustila is an easy one hour drive north-east of Helsinki, approximately 61°N, and 40m above sea level. Mean annual high temperature is 17°C in July, and the low -8°C with snow covering the ground to a depth of up to 100cm from late December until early April. Mean annual rainfall is just 600cm with frequent summer droughts and prolonged spells of extreme cold in the winter – trees growing here have to be tough to survive!

The arboretum began in around 1900, under the ownership of State Secretary A F Tigerstedt, a mining engineer by training. His son C. G. Tigerstedt shared a passion for trees and in 1920 his interests in evolutionary biology and horticulture led to the planting of some 500 exotic woody plants and perennials in the following two decades. Introductions were not based solely on aesthetics, but grounded in science.

All potential species have been carefully screened, climatic conditions examined, and only provenances with matching climates to that at Mustila selected. With his interest in evolutionary biology C. G. Tigerstedt realised that capturing the genetic diversity in a target population was important to give the introductions the best chance of thriving in the harsh Finnish climate.

The methodical approach paid off and has resulted in the outstanding feature of Mustila, forest scale plantings of species such as the Pacific silver fir (Abies amabilis), Macedonian pine (Pinus peuce), Serbian spruce (Picea omorika), and western red-cedar (Thuja plicata). But what makes these even more special is the extensive regeneration; the impressive mature trees complemented by several generations of saplings. The resulting age structure perhaps hints at what stands of the species might look like in their native habitat. Pacific silver fir has been so successful that a third generation is now growing at Mustila.

Today there are around 60 conifers, 150 broadleaves, and around 750 shrubs and perennials planted here, all blending quietly with the native flora, much of which will be familiar to any hillwalker in the UK. Cowberry, crowberry, and bilberry are plentiful along with beech and oak ferns, club-mosses and heathers. With only a handful of staff to help Kimmo Kuusisto has a huge task on his hands, but since its inception the key here has been selecting species and provenances that are a close match for local conditions, working with the site and minimising the efforts required for the collection to thrive. Five hours isn’t enough to really explore this sublime place, and for anyone with even a passing interest in trees it’s well worth at least a day of your time.

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Matthew Parratt and Kimmo Kuusisto exploring the successful appraoach to species introductions at Mustila Arboretum