The life cycle of a pine tree usually varies from 100 years to 1.000 years. The known oldest pine tree is about 4.800 years old and is considered to be one of the oldest living organisms in the World. Today there are more than 180 different species of pines, and they are typical trees found in the northern region of our planet. As it is widely available, it is one of the most used lumber types for the production of furniture and houses.
The life cycle of a pine tree can be divided into 22 stages.
In the first stage, female and male cones are produced on a fully-grown pine tree. Male cones are also known as pollen cones, while female cones are called ovuliferous cones. When the female cones get fertilized by male cones, they turn into seeds from which a pine tree can start to form.
In the next stage, many male cones are formed under new pine tree candles or shoots. During the start of the growing season, which is spring, you can easily spot them when pine trees have not reached their full height. Another way to spot new candles is by checking on their branches, where you can see bright green colored branches.
From this point on, no big visual changes can be spotted by young pine enthusiasts as the processes will take place within a pine tree, or their cones, to be more exact. In this stage, male cones will start to align around the central part of a stalk.
In the fourth step, the pollen sac comes into play. The pollen sac is a pouch or a pocket where the pollen is formed. Pollen is necessary so that the male cones can start to interact with female cones. What also happens in this stage is that the pollen sac will go through meiosis. Meiosis is a process where the number of chromosomes is reduced. After that, many microspores will start to form.
In the fifth step, microspores will start to grow or develop into grains while still being attached to surrounding microspores. Around each grain, a thick two-zoned wall will start to evolve, some of them filled with air.
In the sixth stage of the life cycle of a pine tree, the microspores will start to separate. Every microspore has a single set of unpaired chromosomes, meaning they are genetically altered from their parent plant. After some time, the microspores will start to germinate and are released. This allows the pollen grains to be transported via gusts of wind to other pine trees and their female cones.
During those six stages, female cones have been established at the top of the branches. Female cones are made of many fertile scales, which are similar to male cones, also aligned around the central part of a stalk. The scales of female cones are opened a little bit from each other to allow the pollen to fall between and reach the ovule.
The pollen will fall on damp droplets, that have been excreted by each ovule. Thanks to microscopic air sacs, the pollen can float into the ovule and reach the sporangium. The sporangium is a receptacle in which spores are formed.
In the next stage, a cell that produces haploid spores will go through meiosis or a process where something is divided into four parts. Only one-fourth will remain and continue in the life cycle of a pine tree. The other three fourth will be excluded and shriveled.
Stages #8 to #19
During the other nine internal stages, the ovules have developed into seeds. From this point on, you can see the stages of the life cycle of a pine tree. The entire ovuliferous cones have grown into a woody and tightly closed pinecone. This is necessary to protect the seeds that are within the female cone.
In the twentieth stage, the female cones will slowly start to open to allow the seeds to be released and carried away by the wind. When someone talks about pine cones, this is usually the picture of a pine cone that comes up first in our head.
Stages #21 to #22
Now in case both of the ovules get pollen, there will be two fully formed seeds on each scale. Each seed has wings that allow them to be carried away by the wind. After the wind has carried them away from the parent tree, the seed will start to germinate. Usually, the time needed for a seed to germinate is a couple of weeks or months. To germinate, it needs a cooler temperature and rather moist conditions.
Typically, there are about 150 seeds in each pine cone, and the whole process of growing seeds will take roughly one and a half years. It might seem like a long time if we compare it with the expected lifetime of a person, but it is a rather short period if we think about the estimated lifetime of a pine tree.
Now, after you know everything about the life cycle of a pine tree, it is time to start growing your own from seed! If you want to start growing your pine tree, it is best if you wrap the seed in a moist paper towel. This is a guaranteed method to give the most desirable environment for growing seeds. There are tons of video tutorials available on the web.