Winter Plant Adaptations Study in Northern Lakes

1. Erasmus + February 2018 • Vegetation picture: Petriina Heikkinen

2. Ourfieldworkareas • Placeswherewehavestudied and observedvegetationare Lake Oulujärvi and Lake Saarijärvi in Rokua. • The fieldworkarea of Lake Oulujärvi is 1,7 km from Vaala School Center. • Saarijärvi is locatedabout15 km fromthe center of Vaala

3. School center Lake Oulujärvi

4. SAARIJÄRVI, VAALA

5. How doplantsprepare for thewinter? • Winter putsplantsunder a survivalmode • Plantshave to adapt to coldertemperatures, snowcoverand a shortertime of lightness. • Snow, frost and coldnessarethingsthatplantshave to adapt to butduringthe wintertimeplantsarealsodependent on the snowcover. Northernspecieshavea long evolutiontrying to adaptto thesephenomena.

7. Ourfieldstudyresults: Lake Oulujärvi (Sahanranta) and Lake Saarijärvi (Rokua) One of ouraimswasto observeplants and theirdifferentways to survivethrough the northernwinter. During the time in the wildswewereable to spotthe followingplantsorpieces of plants. • Pine • Birch • Somedeadparts of cowparsley • Spruce • Some lichensunderthesnow cover • Blueberrytwigs

8. Birch Picture: Petriina Heikkinen

9. Cowparsley Pine Pictures: Petriina Heikkinen

10. Pine Pine is one of theplantsthatdoesn’tdropitsleaves in theautumn. Pineneedlesareslim, small and waxywhichreduces the waterlossthrough the transipiration, theystaygreenthrough the winter. Needlescontainchemicalthatpreventsanimalsfromeatingthem, especiallyelkseatyoungpinetwigsduringthe winter. The rootsof a pinedonot stop growing in the wintertimebuttheyreachdeeper to findmoisture and nutrients. Thickbarkprotects the treefromfreezingduring the winter. Cone-shaped, flexibeltwigshelp them to cope with the heavy snowfall. Stayinggreenduring the winterhelpsthem to startproducingenergythroughphotosynthesisearly in the spring. The beginningof the winter and the earlyspringare the mostdangeroustimes for treeslikepines, because the sunlightmakes the tree to evaporatemore and morewater. If the goundis frozen (frost) the rootscannotreplace the loss of evaporatedwaterwhichcancausedamage to the tree. Picture: Petriina Heikkinen

11. Birch A birchis one of the treesthatdropsitsleaveswhen the temperaturesdropdown and the amount of daylightgetssmaller. Thetreetakestheimportantchrolophyllfromitsleaves and storages it into itsroots and trunk. The chrolophyllis slowlydissappearingfrom the leavesand causesthe phenomenoncalledautumnleaves (ruska=forestglowing with autumntints). The bark of birchesis light-colored and reflectivewhichmakes the sun’sradiationnotto affectanychange on the treestemperaturebut the temperature inside the barkstays the sameday and night. That is howthetreeavoidsthedamagecausedbyfastheating and coolingduringthewinter New buds for the nextspringhavealreadystarted to growupduring the last summer. Like most of the trees the birchhasalsoa system on itsbudswhichhelps the treeto protect the budsfromcoldand wind. Birchbranchesarehardy and flexibel and cancarry a big snowcoverwithoutgettingbroken, sprucetwigsinsteadareeasierto getdestroyedespecially in the latewinterwhen the snowcover on the tree is bigger and compacter and due to thatweighsmore. The sprucecrown is reallysensitive to breakunder the weight. Picture: Petriina Heikkinen

12. Snowcover and plants Winterswith a thinsnow cover cancauseproblemsespecially to specieslikeblueberry and heather, because the snow cover protects the livingparts of the plantabove the groundfrom the coldweather (the insulatingeffect of the snow) Snowcover is not just a protect for the coldweatherbut it canalso help the seeds of the plants to spread on a largerarea, since the snowflattenssomelittlelandformswhichallow the wind to moveseeds on the snow. A heavy snowcoverespeciallyduringthelatewintercanalsocausedamage to theplants, especially to trees.

13. Frost and plants During the timewhenfrostis appearingespecially the plantsthataregrowingnear the ground and haveshortroots stop growing. The treesthathavelongerrootscancontinuegrowingdeeperevenduring the timewhenfrostexists on the surfacelayer of the ground. Due to the snowcover and frost the rootscanbeisolatedfrom the outside temperaturethat is colderthan the temperaturein the groundunder the snow. Picture: Petriina Heikkinen

14. Conclusions • Thetemperaturesarerisingdue to thewarmperiodwearelivingthrough and alsodue to theincreasedamount of greenhousegases. The depth and the thicknessof snow cover is changing. Alsosomedifferencesin the thickness of the frostlayercanberecognised. Thesechangesappearto bemoreradical in someareas. • The changes in the snowcover and frostdepthare the evidenceof risingtemperatures. Thesechangesmakealsoplants to changetheircurrentways of surviving. Some of the appearingchangescanbehelpfulto the plantsbutsome of themcanalsocausedamage to them. Both the positive and the negativeeffectscanbenoticed in the wholeecosystem.

15. Sources • https://kartta.paikkatietoikkuna.fi/?lang=fi • Luonto talvella, Sonia Eriksson, Hans-George Wallenius, Gummerus, 1986 • http://www.chicagotribune.com/lifestyles/home/ct-sun-1120-garden-morton-20161114-story.html

16. Grazie mille! Kiitos paljon! Tacksåmycket! Thankyou! Venla, Petriina Alessandro, Andrea Lorenzo, Luca, Alice Picture: Venla Mankinen