A Natural History of Conifers

Aljos Farjon

Royal Botanic Gardens, Kew

Conifers

• What are conifers?

• The image problem

• Systematics and evolution

• The success of the conifers

• Conifer geography

• Conifers and people

• Conservation

What are conifers?

The image problem with Chrismas trees and hedges

• Insert a picture of a hedge here

Picea abies

Abies magnifica Abies forrestii

These are the conifers

we are all familiar with

but…

Do all conifers inthe world

look like these?

• INSERT PICTURE OF DIVERSE NZ

CONIFERS HERE

Dacrycarpus dacrydioides

Phyllocladus hypophyllus

Halocarpus bidwillii

Microcachrys tetragona

Dacrydium araucarioides

What is a conifer?

• Conifers are gymnosperms

• Not all gymnosperms are conifers

• Are conifers gymnosperms with cones?

• Not all gymnosperms with cones are conifers

• Some conifers have cones, others don’t

• Do conifers have anything in common that other

gymnosperms don’t have?

• What is it?...........Answer: a common ancestor!

Encephalartos altensteinii has cones but is not a conifer

Ginkgo biloba does not have cones and is not a conifer

Torreya nucifera does not have cones but is a conifer

Welwitschia mirabilis

Gnetum camporum

E. virginiana

Ephedra intermedia

Evolution and ancestors

• To understand what conifers are, we must try to reconstruct their evolution

• Evolution has to do with ancestors and descendants

• Evolution is also about characters and how they have evolved

• This story begins with the origin of seed plants

• Conifers are a branch on the evolutionary tree of seed plants

The fossil seed cones of Geinitzia formosa from the Santonian in Germany

In a cladogram we canrepresent hypotheticalrelationships of all knownfamilies of conifers thatare known, both extinctand extant.

These relationships arebased on shared derivedcharacters and help usto reconstruct anevolutionary tree ofconifers.

An evolutionary tree ofthe conifers

• 20 families

• 12 extinct

• 8 extant

• The Permo-Triassic extinctionheralded the beginning ofmodern conifers

• Nothing dramatic happenedat the K-T boundary

Fossil and extant conifers

• Evolution of the seed cone of conifers

• Modern examples

Frank White del.

Frank White del.

Frank White del.Abies sp.

Heidiphyllum elongatum Odyssianthuscrenulatus

Telemachus elongatus

Abies forrestii

Pinus wallichiana

Araucaria araucana

Widdringtonia cedarbergensis

Juniperus californica

Podocarpus macrophyllus

Prumnopitys andina

The success of the conifers

• Most speciose group of gymnosperms – 615 species

• Distributed on every continent except Antarctica

• Arid deserts to tropical rainforests

• Dwarf shrubs to the tallest trees, including rheophytes & parasites

• Pioneers to emergent long-lived trees

Sequoiadendron giganteum

Sciadopitys verticillata

Juniperus californica

Pinus pinea

Pseudolarix amabilisDacrycarpus dacrydioides

Agathis australis

The taxonomy of success

• Species diversity concentrated into few large genera (Pinus, Abies, Juniperus, Podocarpus)

• Greatest morphological and ecological diversity in Pinus

• Few medium size genera

• Many small relictual genera

Pinus engelmannii

Pinus pungens

Pinus ponderosa

Juniperus occidentalis

Juniperus occidentalis

Juniperus flaccida

Podocarpus brassii

Podocarpus totara

Podocarpus totara

Wollemia nobilis

Parasitaxus usta

Fitzroya cupressoides

The ecology of success

• Longevity: outlive your competitors

• Adaptation to niches at the edge of angiosperm success

• Pyrophilia: using fire to keep your place in the succession

• Zoochory: the success of Taxus, Podocarpus & Juniperus in imitating angiosperm dispersal tricks

Sequoiadendron giganteum

Sequoiadendron giganteum

Juniperus californica

Pinus pinea

Pinus pinea

Taxus baccata ‘Lutea’

Conifer geography

• Only 615 species but a world-wide distribution

• Vast ranges in the north, but few species

• Small ranges in the subtropics and the south, with many species

• About 200 species occur in the tropics

• 44 of these are in New Caledonia

• 335 species are limited to the Pacific Rim

WORLD DISTRIBUTION OF CONIFERS

Picea glauca

Larix decidua

Cupressus sempervirens

Taxodium distichum

Araucaria angustifolia

Cunninghamia lanceolata

Pinus wallichiana

Dacrydium xanthandrum

Callitris muelleri

Actinostrobus arenarius

Thuja plicata

Sequoia sempervirens

Cupressus macrocarpa

Pinus balfouriana

Pinus coulteri

Pinus devoniana

Araucaria araucana

Phyllocladus aspleniifolius

• Insert picture of Araucaria columnaris here

Araucaria columnaris

Agathis ovata

Araucaria bidwillii

Sciadopitys verticillata

Conifers and people

• Conifers provide 60% of the world’s wood

for industry

• Conifers are almost synonymous with

horticulture

• Conifers are edible (just)

• Conifers have spiritual meaning

Avenue at Bicton, Devonshire

Araucaria araucana

Taxodium mucronatum

Conservation

• Over 30% of conifers are threatened with

extinction

• 25 conifers are Critically Endangered (CR)

• Few reserves are established centred on

conifers

• Conserving conifers often means

conserving ecosystems

Fitzroya cupressoides

Taiwania cryptomerioides

Cedrus libani Araucaria rulei

Juniperus oxycedrus

Retrophyllum minus Xanthocyparis vietnamensis

Dacrydium guillauminii

Pinus rzedowskii

Credits

This presentation owes credit to the following who have contributed images:

Martin Gardner Alexander Schmidt

Martin Hamilton Stephan Schneckenburger

Laura Jennings Derek Spicer

Chris Page Robert Van Pelt

Edward Palmer Tim Waters