Look at your trees.
Walking regularly through your truffière is a luxury that small growers can afford. Finding a tree in each quadrant that you always check is an alternative in a bigger plantation . If you pick a tree and take a regular photograph (on your phone perhaps),save it and keep it to refer to each season. This will also give you some sense of how quickly the trees are growing, or if there is discolouration from pests or disease.
Using drone images is a way to see quickly what trees are healthy and are unstressed by moisture loss ( this may be an indicator of good root growth and therefore more truffles). The Spanish IRTA experiments suggest that maybe the truffle is actual a predator in the relationship we have considered ‘symbiotic’. That might suggest that the truffle will cause stress to the tree to get what sugars it needs.
It’s still early days for the technique outlined below and this 2016 season data has to be correlated to judge its value.
Long term NDVI imaging and if this shows root growth and mycorrization is under way at two locations, and we’ll have the results here in the WIKI. What we do know is that first observations seem to show that the bright red trees have historically produced the most truffle. If this can be used to ensure that you check more carefully the other trees marked like that, that would be a useful pointer. How this will display with deciduous trees vs evergreen also needs to be decided. The above images were taken in April 2015 at Blue Frog Truffle Farm in Sutton NSW.
Our eyes perceive a leaf as green because wavelengths in the green region of the spectrum are reflected by pigments in the leaf, while the other visible wavelengths are absorbed. This same principle applies to wavelengths beyond the visible range and using a drone with near infrared (NIR) cameras can measure the spectrum of absorption and reflection. This provides information about the water content of the plant’s tissue which is related to its developmental status, health and productivity.
In healthy vegetation, chlorophyll absorbs energy from blue and red light to fuel photosynthesis and thereby convert light energy into chemical energy. This chemical energy is stored, primarily in sugars, and forms the basis of production for all other constituents of the plant. Plant tissue with high water content reflects less near infrared radiation than tissue containing less water. In fact, NIR reflectance is inversely proportional to water content.
As trees dry it changes the NIR-absorption of the leaves in the band between 1,450 and 1,600 nm. Blue/green colours represent high water content while yellow/red colours represent low levels.
This is then the source for creating a Normalised Difference Vegetation Index – NDVI
Interpreting that NDVI (Normalised Difference Vegetation Index) results is explained in this video
.
Digital Falcon drone NDVI mapping of truffles at Blue Frog Truffles – April 2016
Look at the leaves and branches
Video from 2015 workshop.
Look at the roots
Examining the root growth of your trees is an invasive method of ascertaining if the roots have good mycorrhiza and the nodules that will become truffles. But on selected trees it remains the only method outsdie of large scale DNA tests for the small grower.
See the video from Celeste here.
Check the soil mycelium
Testing soil for DNA and why it is important