That's according to professor Matthew Walker, who is the director of the Center for Human Sleep Science at the University of California, Berkeley. His book, called Why We Sleep: The New Science of Sleep and Dreams has just been released. Lack of sleep has been linked to many diseases - from cancer to Alzheimer's - as well as obesity, diabetes, and poor mental health.

"Once you know that after just one night of only four or five hours' sleep, your natural killer cells - the ones that attack the cancer cells that appear in your body every day - drop by 70%, or that a lack of sleep is linked to cancer of the bowel, prostate and breast, or even just that the World Health Organisation has classed any form of night-time shift work as a probable carcinogen, how could you do anything else?" 

It's a huge problem that affects us personally. And it also affects our businesses.

Of all of the factors relating to successful employee retention, one of the most important is employee development.

An employee that feels secure and proud with how their career is developing will be a loyal employee. Unfortunately, this is an area in which a lot of business owner's struggle. There are a vast array of reasons that employers do not help their employees achieve their goals.

Why should you have an employee development program in your tree business? Why should you send them to the Texas Tree Conference?