The Pinetum

The Pinetum is an area in the Arboretum often overlooked by visitors to RBG. Unlike the name “Pinetum” seems to imply, pines are not the only variety of trees to be found in this area.  Instead, there is a collection of a variety of conifers that has seen significant additions this past year. The pine family (Pinaceae) being the largest conifer family is rightly well represented with many specimens from the largest genera of Pinus (pines), Abies (true firs) and Picea (spruce) as well as the less populated genera of larches, hemlocks and Douglas fir.  There are also a large number of members of the cypress family (Cupressaceae) in the collection, namely the popular genus Juniperus (juni pers) along with many Chamaecyparis (false cypress) and the newer additions of Cryptomeria japonica (Japanese cedars) found at the entrance to the Pinetum Trail.

Douglas fir

There is so much that can be written about this collection, but in keeping with the approaching season, let’s look more closely at the pine, firs and spruce that are often used as Christmas trees and examine how they can be differentiated. 

If you would like to see the more popular Christmas tree choices have a look here:

http://www.realchristmastrees.org/dnn/Education/TreeVarieties.aspx

The best place to start conifer identification is to look at the needles, since pine needles are bundled with usually 2, 3 or 5 in a bundle while spruce and fir needles are found singly. Take a look at the chart below to see the major differences between these two. (For brevity cones and tree shape will not be dealt with in this article.)

Needle characteristics	Spruce (Picea)	Fir (Abies)
SHAPE	Four sided – will ‘roll’ between your fingers	Flat – will not roll
FEEL	Stiff, sharply pointed	Softer than spruce
LENGTH	No consistent differences
ARRANGEMENT ON THE BRANCH	In spirals around the branch giving it a three dimensional look.	The branch has a flattened appearance
WOOD ON BRANCHES	Needles are attached to woody projections, so branch is rough after needles fall	Branch is smooth after needles fall with a scar left by the needle

A spruce with four sided needles.
Needles are attached singly and spiral
around the branch.

A fir with flat needles.
Needles are attached singly and tend to spread
to the sides to give a flattened appearance to the branch.

A pine branch

There are up to 100 species of pines, however the most common Ontario species can be differentiated by examining the needles.  The Eastern White Pine has long needles in bunches of 5, while the Red Pine has long needles in bunches of 2.  Pitch pine needles occur in threes.  Scots Pine and Jack Pine both have shorter needles in twos, but the Scots Pine needles are twisted, while those of Jack Pine are not.

White pine with needles in groups of five

Red pine with needles in groups of two

Jack pine - needles are in twos, but shorter than
the Red pine

To learn more about any of the genera of conifers, go to the web site for Ontario Trees & Shrubs and click on the genus name.  You can also use the list on the left of the page to change your search criteria.

http://ontariotrees.com/main/list_genus.php