Using a botanic garden collection to test a bioclimatic vegetation scheme

Vegetation maps and bioclimatic zone classifications communicate the vegetation of an area and are used to explain how the environment regulates the occurrence of plants on large scales. Many practises and methods for dividing the world’s vegetation into smaller entities have been presented. Climatic parameters, floristic characteristics, or edaphic features have been relied upon as decisive factors, and plant species have been used as indicators for vegetation types or zones. Systems depicting vegetation patterns that mainly reflect climatic variation are termed ‘bioclimatic’ vegetation maps. Based on these it has been judged logical to deduce that plants moved between corresponding bioclimatic areas should thrive in the target location, whereas plants moved from a different zone should languish. This principle is routinely applied in forestry and horticulture but actual tests of the validity of bioclimatic maps in this sense seem scanty. In this study I tested the Finnish bioclimatic vegetation zone system (BZS). Relying on the plant collection of Helsinki University Botanic Garden’s Kumpula collection, which according to the BZS is situated at the northern limit of the hemiboreal zone, I aimed to test how the plants’ survival depends on their provenance. My expectation was that plants from the hemiboreal or southern boreal zones should do best in Kumpula, whereas plants from more southern and more northern zones should show progressively lower survival probabilities. I estimated probability of survival using collection database information of plant accessions of known wild origin grown in Kumpula since the mid 1990s, and logistic regression models. The total number of accessions I included in the analyses was 494. Because of problems with some accessions I chose to separately analyse a subset of the complete data, which included 379 accessions. I also analysed different growth forms separately in order to identify differences in probability of survival due to different life strategies. In most analyses accessions of temperate and hemiarctic origin showed lower survival probability than those originating from any of the boreal subzones, which among them exhibited rather evenly high probabilities. Exceptionally mild and wet winters during the study period may have killed off hemiarctic plants. Some winters may have been too harsh for temperate accessions. Trees behaved differently: they showed an almost steadily increasing survival probability from temperate to northern boreal origins. Various factors that could not be controlled for may have affected the results, some of which were difficult to interpret. This was the case in particular with herbs, for which the reliability of the analysis suffered because of difficulties in managing their curatorial data. In all, the results gave some support to the BZS, and especially its hierarchical zonation. However, I question the validity of the formulation of the hypothesis I tested since it may not be entirely justified by the BZS, which was designed for intercontinental comparison of vegetation zones, but not specifically for transcontinental provenance trials. I conclude that botanic gardens should pay due attention to information management and curational practices to ensure the widest possible applicability of their plant collections.

Sireenit, floksit ja iirikset- Puu-Käpylän koristekasvit

Puu-Käpylä (“Wooden Käpylä”), a neighbourhood of Helsinki, is the earliest example of the Garden City Movement in Finland. The suburb of valuable wooden architecture was built between 1920 and 1925, with the aim to provide a healthy housing area for working-class families with many children. The houses were erected by a co-operative (Käpylän kansanasunnot, “People?s Dwellings”) and they are protected by the city plan since 1960?s. However, the historical value of the sheltered courtyards has not been investigated. The aim of this study was to survey the garden flora of Puu-Käpylä and to evaluate the authenticity of the courtyard gardens. The survey covered the area of one residential quarter (1.2 ha) with twelve 2-storey semi-detached timber houses arranged around a common yard, which was originally appointed for the tenants? vegetable gardens. The houses are still rented, and each flat is allowed a small lot of the courtyard for cultivation. A complete list was made of all perennial, ornamental plant taxa present in the quarter. Spring bulbs were missed due to the timing of the survey. Generally, the plants were recorded on species level, with the exception of common lilacs, shrub roses, irises and peonies that were thoroughly studied for cultivar identification. It was assumed that plants initially grown in the courtyard could be distinguished by studying Finnish garden magazines, books and nursery catalogues published in the 1920?s and by comparing the present vegetation to surviving documents from the quarter. The total number of ornamental plant taxa identified was 172, of which 17 were trees, 47 shrubs, 7 climbers and 101 herbaceous perennials. The results indicated that a major part of the shrubs, climbers and perennials presumably originated from the 1970?s or later, whereas ca. 70 % of the tree specimens were deemed as original. The survey disclosed a heritage variety of common lilac, resembling cultivar „Prince Notger?, a specific peony taxon, Paeonia humilis Retz., cultivated in Nordic countries since long ago, and a few historic iris varieties. Well-preserved design elements included front gardens on one side of the quarter, a maple alley on another side as well as trees at the garden gates. Old garden books and magazines did not shed much light on the Finnish garden flora commonly used in the period when Puu-Käpylä was built. However, they gave a valuable picture of contemporary planting design. Nursery catalogues offered insight into the assortment of ornamental plants traded in the 1920?s. Conclusions on the authenticity of the current flora were mainly drawn on the basis of old photographs and a vegetation survey map drawn in the 1970?s. This study revealed a need for standardization of syrvey methods applied when investigating garden floras. Uniform survey techniques would make the results comparable and enable a future compilation of data from e.g. historic gardens.

Havupuiden erikoismuotojen lisäysmenetelmät

Havupuiden erikoismuotoja on käytetty koristekasveina jo vuosisatoja ympäri maailmaa. Niitä on lisätty pääsääntöisesti pistokkaista ja varttamalla. Suomessa kotimaisten metsäpuidemme erikois-muotoja on kartoitettu ja kerätty kokoelmiin järjestelmällisemmin 1960-luvulta alkaen. Taimisto-viljelijät, puutarhasuunnittelijat ja kotipuutarhurit ovat olleet enenevässä määrin kiinnostuneita näistä kotimaisista kestävistä havukasveista. Yli 90 prosenttia markkinoillamme olevista havukas-veista tuodaan ulkomailta, joten on selvää, että niiden talvenkestävyydessä on ongelmia. Tämän tutkimuksen tavoitteena oli selvittää kotimaisille erikoismuodoille sopivia lisäysmene-telmiä ja siten edistää kotimaisen havukasvituotannon mahdollisuuksia. Aineistona kokeissa oli kotimaisia erikoismuotoja metsäkuusesta (Picea abies (L.) Karsten) ja kotikatajasta (Juniperus communis L.), tavallisia metsäkuusia sekä kahdeksan ulkomaista havupuutaksonia. Lisäysmene-telmistä tutkittiin varttamista ja pistokaslisäystä ja kokeet suoritettiin Metsäntutkimuslaitoksen toimipaikoissa Lopen Haapastensyrjässä sekä Punkaharjulla. Varttamiskokeessa vertailtiin koti-maisen kuusen erikoismuotokloonien varttamisen onnistumista. Pistokaskokeissa tutkittiin geno-tyypin, emopuun iän, pistokasoksan sijainnin sekä hormonikäsittelyn vaikutusta havukasvien pis-tokkaiden juurtumiseen. Tavalliset metsäkuuset toimivat kontrolleina. Tutkimus osoitti, että varttaminen onnistui erinomaisesti kaikilla erikoismuotoklooneilla. Ovat-ko vartteet esteettisesti katsottuna koristekäyttöön sopivia, jää vielä seurattavaksi. Pistokaskokeis-sa havaittiin, että juveniilisuus vaikutti pistokkaiden juurtumiseen, mutta iäkkäistäkin puista lisää-minen onnistuu, kunhan genotyyppi on sopiva. Keskimäärin alaoksat juurtuivat paremmin kuin latvuksen yläosista otetut pistokasoksat, mutta vain yhdellä kloonilla ero oli tilastollisesti merkit-sevä. Hormonikäsittely heikensi selvästi kotimaisen kuusen ja katajan pistokkaiden juurtumista, mutta ulkomaisiin havupuulajeihin käsittelyllä ei ollut vaikutusta. Kotimaisen havukasvituotannon pohjaksi pitäisi tehdä kloonivalintaa, jossa koristearvon lisäksi otettaisiin huomioon myös kloonin lisättävyys. Taimien tuottaminen pistokkaista on selvästi edul-lisempaa kuin vartteiden tuottaminen, joskin varte kasvaa myyntikuntoon nopeammin kuin pisto-kastaimi. Pistokastaimi on kuitenkin omajuurinen ja stabiilimpi kasvutavaltaan kuin varte. Tämä korostuu etenkin kääpiömuotoja tuotettaessa.